- Email: [email protected]
Incremental cost-effectiveness of initial cataract surgery
Incremental Cost-effectiveness of Initial Cataract Surgery Brandon G. Busbee, MD,1,2 Melissa M. Brown, MD, MBA,1,3 Gary C. Brown, MD, MBA,1,2 Sanjay Sharma, MD, MBA1,4 Purpose: The purpose of this study was to perform a reference case, cost-utility analysis of initial cataract surgery using the current literature on cataract outcomes and complications. Design: Computer-based econometric modeling. Methods: Visual acuity data of patients treated and observed over a 4-month postoperative period was obtained from the US National Cataract Patient Outcomes Research Team (PORT). The results from this prospective study were combined with other studies that investigated the complication rates of cataract surgery to complete the cohort of patients and outcomes. These synthesized data were incorporated with time-tradeoff utility values, decision analysis, and econometric modeling to account for the time value of money. Main Outcome Measures: The number of quality-adjusted life-years (QALYs) gained was calculated for the study group undergoing cataract extraction in the first eye when the vision was the same in both eyes. This was divided into the cost of the procedure to find the year 2000 nominal US dollars spent per quality-adjusted life-year ($/QALY) gained. Results: Initial cataract surgery, compared with observation, resulted in a mean gain of 1.776 QALYs per patient treated. A 3% annual discount rate was used to account for the benefit over time, yielding 1.25 QALYs gained. The mean cost of treatment (also discounted at a 3% annual rate) of each patient totaled $2525. The cost divided by the discounted benefit resulted in $2020/QALY gained for this procedure. Conclusions: Initial cataract surgery seems to be highly cost-effective compared with procedures across multiple medical specialties. This information, incorporating patient preferences into evidenced-based medicine, will play an increasingly important role in the evaluation of health care in the future. Ophthalmology 2002;109: 606 – 613 © 2002 by the American Academy of Ophthalmology. Cataract surgery with intraocular lens (IOL) implantation is one of the most commonly performed procedures in health care. Many prospective studies have attempted to quantify the outcome of this procedure. The US National Cataract Patient Outcomes Research Team (PORT) and the International Cataract Surgery Outcomes Study undertook the task of analyzing visual outcomes, complication rates, and variation in practice patterns associated with cataract surgery in four countries. The US cohort in this study analyzed both phacoemulsification and extracapsular cataract extraction Originally received: September 20, 2000. Accepted: June 5, 2001.
Manuscript no. 200521.
1
Center for Evidence-Based Health Care Economics, Wills Eye Hospital, Jefferson Medical College, Philadelphia, Pennsylvania.
2
Retina Vascular Unit, Wills Eye Hospital, Jefferson Medical College, Philadelphia, Pennsylvania.
3
Cataract and Primary Eye Care Service, Wills Eye Hospital, Jefferson Medical College, Philadelphia, Pennsylvania.
4
Cost-Effective Ocular Health Policy Unit, Queens Medical College, Kingston, Ontario, Canada. Supported in part by the Retina Research and Development Foundation, Philadelphia, the Canadian Foundation for Innovation, Ottawa, Ontario, the E. A. Baker Foundation, the Canadian National Institute for the Blind, Toronto, Ontario, and the Premier’s Excellence Awards, Ontario Ministry of Science, Energy and Technology, Toronto, Ontario, Canada. Reprint requests to Melissa M. Brown, MD, MN, MBA, Center for Evidence-Based Health Care Economics, 1107 Bethlehem Pike, Suite 210, Flourtown, PA 19031.
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© 2002 by the American Academy of Ophthalmology Published by Elsevier Science Inc.
procedures in approximately a 2:1 ratio.1– 4 In the US patient cohort, 82.5% of patients were found to have a Snellen visual acuity equal to or greater than 20/30 at the 4 postoperative month end point.1 Complications of both phacoemulsification and extracapsular cataract extraction have also been well described in the past two decades. Along with the complication rates of the 772 patients entered in the US arm of the PORT study, many other researchers analyzed even larger numbers of patients and their complication rates after cataract surgery. Reported rates and outcomes of adverse events since cataract surgery have included posterior capsular opacification (PCO), endophthalmitis, cystoid macular edema, pseudophakic retinal detachment, lost lens fragments, lens dislocations, and pseudophakic bullous keratopathy.5–12 The numerous possibilities for visual outcome, with most patients finding an improvement in visual acuity, have led to many attempts to quantify the benefit of this elective surgery to the patient and society. Many studies have focused their measurements on the postoperative functioning of the patients.13–18 There has also been research on the issues of surgery on the second eye and the cost of cataract surgery to society.19 –21 Cost-utility analysis is a method that objectively measures the benefit derived from an intervention for the costs expended.22–31 It incorporates evidenced-based medicine and patient-based preferences (utility values) into a theoretical model accounting for the quality of a patient’s life in a ISSN 0161-6420/02/$–see front matter PII S0161-6420(01)00971-X
Busbee et al 䡠 Cost-effectiveness of Cataract Surgery particular health state. By the convention of utility theory, 1.0 in utility theory is equivalent to perfect health and 0.0 is equivalent to death.32–34 For example, a utility value approaching 1.0 is associated with excellent quality of life, encompassing factors such as the ability to perform activities of daily living and lack of anxiety related to the medical condition. Conversely, a patient-determined utility value approaching 0.0 is associated with a poor quality of life. Utility values recently have been used across medical specialties and theoretically allow for quantitative comparison among treatments in varied fields.17,28 –31 In the field of ophthalmology, utility values have been shown to be directly proportional to the Snellen visual acuity in the better-seeing eye. In a cohort of more than 300 consecutive patients, it has recently been shown that age, race, education, gender, socioeconomic status, length of time of disease, and the particular disease state itself did not alter the reproducibility of utility values correlated with different levels of visual acuity.35 In this study, utility values were incorporated into cost-utility analysis to evaluate the cost-effectiveness of initial cataract surgery.
Material and Methods Overview Decision analysis incorporating utility values was performed using software produced by Treeage, Inc., (Williamstown, MA).36 The clinical situation of cataract extraction with IOL implantation was simulated in the decision analysis tree.37 Because this study focused on the patient’s first cataract surgery and the procedure was definitive (i.e., recurrence rate of cataract is 0), Markov modeling was not used in this cohort. It was also assumed that the visual acuity in the fellow eye was equal to the preoperative vision in the eye undergoing cataract surgery. Visual acuity data in the fellow eyes were not reported by the PORT study. The microcomputer model performing decision analysis took into account the complications, as defined by the authors, and also the mortality within the group of patients. The median patient age in the PORT study was 73 years. This number was applied to current life tables to determine life expectancy.38
Cataract Extraction Patient Sample The patients from the US National Cataract PORT were studied to obtain visual acuity results in patients undergoing cataract extraction. The patients in the international arm of this collaboration were excluded from this study. These patients were excluded because of the fact that only in the US arm of the study did the procedure performed most closely resemble the standard of care in the US health care system. In this cohort of 722 US patients enrolled between July 1991 and December 1991, phacoemulsification was performed on 67.3% of the patients. In Canada, Denmark, and Spain the rates of phacoemulsification during the same period were to 63%, 33%, and 2%, respectively.1 The PORT cohort of patients had an end point of 4 months since cataract surgery. The authors recognize that the complications of endophthalmitis, macular edema, and lost lens fragments typically occur within this 4-month window. The visual sequelae in eyes with these complications are therefore included in the PORT 4-month data. Thus, the decision analysis tree to simulate visual acuity results over the lifetime of the patient excludes
endophthalmitis, macular edema, and lost lens fragments in determining visual results (Fig 1). A synthesis of large studies, totaling more than 58,000 patients, shows similar complication rates among these studies and the PORT study.1,5,6,9 –12
Cataract Extraction Complication Rates and Visual Results PCO. The rate of 28% over 5 years was used for PCO following cataract extraction.6 The mean time of treatment after surgery was assumed to be 2 years.6 An increased rate of retinal detachment after treatment of the PCO by yttrium–aluminum– garnet (YAG) capsulotomy was included in the visual results. Javitt et al39,40 reported a 3.9-fold increase in the cumulative retinal detachment rate of 0.81% after cataract surgery. The authors made the assumption that visual acuity returned to postoperative baseline after YAG capsulotomy in the 96.8% of patients who did not experience the complication of retinal detachment. Endophthalmitis. The PORT study only had one patient in the cohort who developed postoperative endophthalmitis.2 The authors believe this is an accurate outcome because of size of the patient cohort. The endophthalmitis rate used in this study was 0.13%.9 The visual result of this is included in the mean, 4-month postoperative visual acuity. Lens Dislocation. The rate of 1.1% was used for lens dislocation after cataract extraction.9 The visual result since IOL repositioning, exchange, or removal was derived from a weighted average of slightly better than 20/50 from Mello et al.5 Cystoid Macular Edema. The PORT study observed postoperative ophthalmoscopic cystoid macular edema in 3.21% of patients.2 The visual result from this complication was included in the mean 4-month postoperative visual acuity. Pseudophakic Bullous Keratopathy. The rate of 0.3% was used for pseudophakic bullous keratopathy after cataract surgery.9 The resultant visual acuities were derived from a weighted average from Cohen et al.10 This visual acuity of 20/85 corresponded to a utility value of 0.70 in the 70.7% of patients who underwent penetrating keratoplasty. The surgical treatment of pseudophakic bullous keratopathy was assumed to occur 1 year after cataract surgery. The visual acuity of counting fingers in the 30.3% of patients who did not have surgery corresponded to a utility value of 0.52.10,35 The medical costs for this treatment were assumed to occur over the lifetime of the patient. The utility value used for nonsurgical pseudophakic bullous keratopathy was equivalent to that of patients who received penetrating keratoplasty when applied to the Markov model, however. This assumption was made, because counting fingers vision would most likely correspond to the worse-seeing eye. Therefore, the same utility value of 0.70 was used for patients treated with medical therapy. Lost Lens Fragments. In the PORT study, 0.28% of patients who underwent cataract extraction experienced lost nuclear material in the vitreous.2 The visual result of this was included in the mean 4-month postoperative visual acuity. Retinal Detachment. The rate of 0.81% was used for retinal detachment after cataract surgery.38 The mean time of retinal detachment repair was assumed to occur a year after cataract surgery, unless a YAG capsulotomy was performed, in which case retinal detachment was assumed to occur 1 year after the capsulotomy. The resultant visual acuity of slightly worse than 20/70 was derived from a weighted average reported in the publication by Greven et al.12
Conversion of Visual Acuity to Utility Values A patient preference– based, time tradeoff method was used to derive utility values associated with the best-corrected visual acu-
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Ophthalmology Volume 109, Number 3, March 2002
Figure 1. Decision analysis tree for cataract management. Utility values are located to the right of the decision nodes (triangles). The incidence of events are shown below the arms in the tree. (IOL ⫽ intraocular lens).
ity in the better-seeing eye. Essentially, this is a method by which the patient determines what quantity of time they would be willing to relinquish to have quality of life associated with 20/20 vision. This method of utility measurement has been thoroughly described in the literature.22–27,35 The utility value corresponding to the mean 4-month postoperative visual acuity of 20/27 after cataract extraction is 0.86.1,35 The utility values corresponding to the complications associated with cataract extraction are listed in Table 1.
Medical Costs The health care costs arising from provider services were according to year 2000 Current Procedural Terminology data and the payments by the Health Care Finance Agency in nominal US dollars.41 These payments set by the Health Care Finance Agency take into account the factors of physician work, practice expense, and malpractice expense.42 Any institutional costs incurred as a result of the procedures or admissions related to cataract surgery or its complications were categorized into one of two groups. For ambulatory procedures, the Medicare 2000 outpatient facility fee of $928 was used in this study.43 The second group consisted of inpatient operating room costs and admission, which related to retinal procedures in this study. The diagnosis-related group #36 fee of $2825 was representative of these procedures.43 Costs related to drug expenditures were taken from the average
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wholesale prices as defined in the 2000 Drug Topics Red Book.44 The medications that were included in this study consisted of topical antibiotics, topical steroids and nonsteroids, and topical cycloplegics. The costs and applicable current procedural terminology codes for each procedure are summarized in Table 2. In many clinical scenarios, there is more than one treatment option for a given complication of cataract surgery. For each of these complications, an estimated percentage of patients receiving Table 1. Utility Values Associated with the Treatment of the Complications after Cataract Surgery Complication
Utility Value35
Posterior capsular opacification—no complications Posterior capsular opacification—with complicating RD Endophthalmitis Lens dislocation Cystoid macular edema Pseudophakic bullous keratopathy—treatment with PK Pseudophakic bullous keratopathy—medical treatment Lost lens fragments Retinal detachment
0.86 0.73 NA 0.85 NA 0.70 0.70 NA 0.73
NA ⫽ not applicable, since accounted for in 4-month PORT study data1; PK ⫽ penetrating keratoplasty; RD ⫽ retinal detachment.
Busbee et al 䡠 Cost-effectiveness of Cataract Surgery each treatment option was determined. This allowed for the most accurate assessment, using a weighted average, of the total costs. Each complication and its treatment options are described in the following.: PCO. YAG capsulotomy was the only procedure used to treat this complication. In addition, no facility fee was applied because YAG laser is typically an office-based procedure. Endophthalmitis. Vitreous tap and injection accounted for 80% of endophthalmitis patients in this model. The remaining 20% of patients were assigned to the vitrectomy group.45 Lens Dislocation. IOL repositioning or exchange with accompanying pars plana vitrectomy accounted for 11% of patients with lens dislocation in this model. The remaining 89% of patients had IOL repositioning or exchange alone.5 Cystoid Macular Edema. All patients with this complication incurred treatment costs relating to both topical nonsteroidal (ketorolac) and steroidal medications. Pseudophakic Bullous Keratopathy. Penetrating keratoplasty was the treatment option used for 70% of the patients with pseudophakic bullous keratopathy.10 The remaining 30% of patients incurred treatment costs related to lifetime use of topical 5% sodium chloride solution. Lost Lens Fragments. All patients with this complication incurred treatment costs related to a pars plana vitrectomy and retrieval of the lens fragments. Retinal Detachment. A scleral buckling procedure was the treatment option used for 50% of patients with pseudophakic retinal detachment. The remaining half of patients incurred the costs related to a retinal detachment repair with vitrectomy (personal communication, GC Brown on the practice patterns of the Retina Service at Wills Eye Hospital, August 2000).
Present Value Analysis The initial outlay of dollars for the preceding expenditures was assumed to occur at the initiation of therapy. The treatment effect gained from those dollars remains over the lifetime of the patients. Thus, discounting was used to account for the time value of money26,45,46 The annual discount rate used in this study was 3% for both costs and health benefits (quality-adjusted life-years [QALYs] gained).
Results A resultant, mean utility value of 0.858 was obtained using decision analysis for patients undergoing initial cataract surgery. This value takes into account the risks and deleterious effects of complications over the remainder of the patient’s life. For patients who did not undergo cataract surgery over their lifetime, a utility value of 0.71 was assigned. This corresponded to the mean preoperative visual acuity of 20/83 found in the PORT study.1 The net utility gain for initial cataract surgery was thus 0.148. The decision tree used to calculate the number of QALYs gained is shown in Figure 1. A life expectancy of 12 remaining years in this cohort, multiplied by the net utility gain, resulted in 1.776 QALYs gained by cataract surgery.38 Cataract surgery and its related expenditures for complications resulted in a total health care cost of $2525. This encompassed the costs of complications that were included in the 4-month postoperative data, as well as those (i.e., retinal detachment, corneal edema) occurring after 4 months. Present value analysis was accounted for by discounting the initial benefit of the intervention, or 1.776 QALYs gained. By incorporating a 3% annual discounting rate, the final number of QALYs gained from the procedures, over the remaining lifetime of the patient, was 1.25.
The resultant cost-effectiveness (dollars spent per quality-adjusted life-years [$/QALY]) gained from initial cataract surgery was found to be $2020.
Sensitivity Analysis One-way sensitivity analysis was performed varying costs, utility values, and the discount rate. When the total costs were increased by 25%, the $/QALY gained was $2525, whereas decreasing costs by 25% yielded a $/QALY gained of $1515. Raising all utility values by 25% yielded a $/QALY gained of $1605, whereas lowering them by 25% yielded a $/QALY gained of $2703. Varying the yearly discount rate resulted in a $/QALY gained of $1432 for a 0% rate, $2544 for a 5% rate, and $4398 for a 10% rate.
Discussion The data presented herein suggest that cataract surgery with IOL implantation is a very cost-effective intervention using conventional standards. Although the standards for costeffectiveness in health care vary from one society to another, depending on the resources that society has to expend, it has been suggested that interventions costing less than $20,000/QALY gained are highly cost-effective, whereas those costing more than $100,000/QALY are not cost-effective.47 With a cost-effectiveness of $2020/QALY gained, cataract surgery falls well within the very costeffective range. Compared with other interventions in ophthalmology, the cost-effectiveness of cataract surgery in year 2000, US real dollars is roughly comparable to that of cryotherapy for threshold retinopathy of prematurity at approximately $1900/QALY gained.25 It is less cost-effective than laser therapy for threshold retinopathy of prematurity at about $700/QALY gained25 but more cost-effective than laser treatment for choroidal neovascularization at approximately $5000/QALY gained.23,24 It is substantially much more cost-effective than the treatment of acute central retinal artery obstruction at about $6 million/QALY gained.48 Concerning nonophthalmologic specialties,35 single-vessel coronary artery bypass surgery for disease of the left anterior descending artery costs approximately $7000/ QALY gained, whereas treatment of systemic arterial hypertension (diastolic, 95–104 mmHg in males, aged 40) costs approximately $58,000/QALY gained, and ambulatory peritoneal dialysis approximately $90,000/QALY gained. Thus, it can be seen that the cost-effectiveness of cataract surgery compares favorably with these commonly performed interventions performed in nonophthalmologic specialties. It should be emphasized that the value gained from cataract surgery in this article is based on patient preferences, or what patients believe are most valuable to them. There is a growing body of literature suggesting that perceptions of value from the patient’s point of view are critical for improving our health care system.49 –51 The authors herein concur that the preferences of patients who experience a health state firsthand are the most valid. It should also be noted that the preferences and values of patients with a health state can differ substantially from those of surrogate
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Ophthalmology Volume 109, Number 3, March 2002 Table 2. Medical Costs (Year 2000 Nominal US Dollars) and Current Procedural Terminology Codes
Service
Current Procedural Terminology Discounted Code41 Cost42
Cataract surgery Initial office consultation A-scan with IOL calculation Cataract extraction Ambulatory surgical center fee Postoperative medications Anesthesia fees58
99254 76519 66984 NA NA NA
$144 $79 $748 $928 $54 $360 Total $2313
Posterior capsular opacification YAG capsulotomy Postlaser medications
66821 NA
$184 $22 Total $206
Endophthalmitis—tap and inject Initial office consultation Vitreous tap Vitreous drug injection Postprocedure medications
99254 67010 67028 NA
$144 $476 $158.50* $63.44 Total $841.94
99254 67036 67028 DRG #3643 NA NA
$144 $870 $158.50* $2825 $63.44 $648 Total $4708.94
66825 NA NA NA
$626 $928 $63.11 $360 Total $1977.11
Endophthalmitis—pars plana vitrectomy Initial office consultation Pars plana vitrectomy Vitreous drug injection Inpatient facility fee Postoperative medications Anesthesia fees58 IOL dislocation IOL repositioning Ambulatory surgical center fee Postoperative medications1–4 Anesthesia fees58
IOL dislocation with pars plana vitrectomy Initial office consultation 99254 Pars plana vitrectomy 67036 IOL repositioning 66825 Inpatient facility fee DRG #3643 Postoperative medications1–3 NA Anesthesia fees58 NA Cystoid macular edema Topical medications3,4
NA
$144 $870 $313* $2825 $63.11 $648 Total $4863.11 $152 Total $152
Pseudophakic bullous keratopathy—surgical Initial office consultation Penetrating keratoplasty Ambulatory surgical center fee Postoperative medications1–3 Anesthesia fees58
99254 65730 NA NA NA
$140 $1062 $901 $61.27 $629 Total $2793.27
Pseudophakic bullous keratopathy—medical Lifetime topical medication5
NA
$1319.08 Total $1319.08
Lost lens fragments Initial office consultation Pars plana vitrectomy Inpatient facility fee Postoperative medications1–3 Anesthesia fees58
99254 67036 DRG #36 NA NA
$144 $870 $2825 $63.11 $648 Total $4550.11
Retinal detachment—scleral buckle Initial office consultation RD repair—scleral buckle Inpatient facility fee
99254 67107 DRG #36
$140 $1091 $2743 (continues)
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Table 2. (continued)
Service
Current Procedural Terminology Code41
Postoperative medications1–3 Anesthesia fees58
NA NA
$61.27 $629.00 Total $4664.27
Retinal detachment—vitrectomy Initial office consultation RD repair—vitrectomy Inpatient facility fee Postoperative medications1–3 Anesthesia fees58
99254 67108 DRG #36 NA NA
$140.00 $1518.00 $2743.00 $61.27 $629.00 Total $5091.27
Discounted Cost42
*Only 50% of the second procedure is included as per Medicare guidelines. IOL ⫽ intraocular lens; 1 ⫽ one 5ml bottle of prednisolone acetate drops; 2 ⫽ one 5ml bottle of atropine drops; 3 ⫽ one 5ml bottle of ciprofloxacin drops; 4 ⫽ two 5ml bottles of ketorolac drops; 5 ⫽ 125 5ml bottles of 5% sodium chloride solution (estimated lifetime supply); CPT ⫽ current procedural technology; DRG ⫽ diagnosis-related group; NA ⫽ not applicable; RD ⫽ retinal detachment; YAG ⫽ yttrium–aluminium– garnet.
responders such physicians, administrators, and the general public.52–54 For this additional reason, it was elected to use patient preferences for this study. Of importance is the fact that this article deals with cataract surgery in the first eye. The cost-effectiveness of cataract surgery in the second eye, which has not been addressed herein, is the subject of another article. Cataract surgery in the second eye is likely to be very cost-effective as well, because the utility values of ophthalmic patients with good vision in two eyes are substantially higher than those of patients with good vision in one eye.55 The substantial worry about the welfare of the good eye in patients who have good vision in only one eye is believed to be a major factor contributing to this utility difference. The cost-utility analysis used herein allows a comparison across all medical specialties of the value received from health care interventions for the dollars expended. Critically, it incorporates an objective measure of the patientperceived improvement in quality of life (as well as the improvement in length of life for select cases) conferred by an intervention. The authors are unaware of another method that allows this type of comparison. The United States has recently been ranked as No. 37 in health care quality in the world by the World Health Organization, which used a method heavily weighted toward the efficient use of medical resources a given society has available.56 Cost-utility analysis provides a potential information system that can help to improve the efficient use of medical resources and improve the quality of medical care at the same time.55 As with any study, there are potential inherent weaknesses in this analysis. The authors acknowledge that typical practice patterns for cataract extraction dictate surgery on the eye with an equal or worse visual acuity. A weakness of this study resides in the assumption that the preoperative visual acuity of the fellow eye was equal to the operated eye in all patients. This assumption had to be made for the model because of a lack of data on preoperative, fellow eye
Busbee et al 䡠 Cost-effectiveness of Cataract Surgery visual acuities in large, prospective cataract extraction studies, including the PORT study. A scenario that potentially would decrease the margin of benefit between the operated and unoperated eye is if the unoperated eye had a preoperative visual acuity substantially better than the preoperative cataract eye. For example, assume cataract surgery was planned in an eye with visual acuity of 20/60, and the fellow eye had a visual acuity of 20/30. Even by performing surgery on the worse eye, the initial utility change would be less substantial than depicted in our model. This is because utility values are derived from the better-seeing eye. Therefore, the preoperative utility value would correspond to 20/30 (fellow eye) and postoperatively to 20/27 (operated eye). This smaller difference, however, would approach the utility change in our study over time because of the expected decline of vision in the fellow eye with the remaining cataract. The authors believe the model presented in this article accurately depicts a generalized clinical scenario for cataract surgery. Additional weaknesses in this study include the incomplete analysis of all the incremental costs of cataract surgery, or those induced by performing the surgery, versus no treatment. The societal costs saved by performing cataract surgery were not included in this analysis. Also, the utility values used in our study were not specifically obtained from patients with cataract, but rather visual loss in general. Many of the patients used to gather original utility data35 had irreversible retinal diseases. This possibly overestimates the value of visual change, because patients who are aware their vision cannot improve might put more value on regaining that vision. It has been shown, nonetheless, that the degree of visual loss itself, rather than the underlying cause, is most closely correlated with utility values.35 To further counter criticism in this regard, altering the utility values by as much as 25% with sensitivity analysis failed to substantially alter the cost-effectiveness of the cataract surgery. There may also be criticism of the concept of costutility analysis in general, but then it must be asked, “What is the preferable alternative?” With an annual health care budget in the United States consuming 14% of the gross domestic product in 2000, and projected to increase to 16.2% of the gross domestic product by the year 2008,57 potential solutions, such as cost-utility analysis, to restrain costs and improve quality of care are highly desirable.55 In summary, cataract surgery in the United States seems to be a very cost-effective intervention by conventional standards. Likely factors that contribute to this are the clinical effectiveness of the surgery, the substantial improvement in patient-perceived quality of life it confers, and the reasonable cost made possible by technological advances and the ingenuity of those involved in the evolution of the procedure.
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medicine, utilities and quality of life. Curr Opin Ophthalmol 1999;10:221– 6. Brown GC, Brown MM, Sharma S, et al. Incremental costeffectiveness of laser photocoagulation for subfoveal choroidal neovascularization. Ophthalmology 2000;107:1374 – 80. Brown GC, Brown MM, Sharma S, et al. Incremental costeffectiveness of laser therapy for choroidal neovascularization associated with histoplasmosis. Retina 2000;20:331–7. Brown GC, Brown MM, Sharma S, et al. Cost-effectiveness of treatment for threshold retinopathy of prematurity. Pediatrics 1999;104:e47. Drummond MF, O’Brien B, Stoddard GL, Torrence GW. Methods for the Economic Evaluation of Health Care Programmes, 2nd ed. New York: Oxford University Press, 1996;52–204. Brown MM, Brown GC, Sharma S, Shah G. Utility values and diabetic retinopathy. Am J Ophthalmol 1999;128:324 –30. Wyatt JR, Niparko JK, Rothman M, deLissovoy G. Cost utility of the multichannel cochlear implants in 258 profoundly deaf individuals. Laryngoscope 1996;106:816 –21. Pinkerton SD, Holtgrave DR, Pinkerton HJ. Cost-effectiveness of chemoprophylaxis after occupational exposure to HIV. Arch Intern Med 1997;157:1972– 80. Jacobson JJ, Schweitzer SO, Kowalski CJ. Chemoprophylaxis of prosthetic joint patients during dental treatment: a decision-utility analysis. Oral Surg Oral Med Oral Pathol 1991;72:167–77. Kent KC, Kuntz KM, Patel MR, et al. Perioperative imaging strategies for carotid endarterectomy. JAMA 1995;274:888 –93. Weinstein MC, Stason WB. Foundations of cost-effectiveness analysis for health and medical practices. N Engl J Med 1977;296:716 –21. Torrance GW. Utility approach to measuring health-related quality of life [review]. J Chronic Dis 1987;40:593– 603. Torrance GW, Feeny D. Utilities and quality-adjusted life years. Int J Technol Assess Health Care 1989;5:559 –75. Brown GC. Vision and quality-of-life. Trans Am Ophthalmol Soc 1999;97:473–511. DataTM 3.5 for Healthcare User’s Manual. Williamstown, MA: Treeage Software, Inc., 1999; pp 9 –16. Detsky AS, Nagile G, Krahn MD, et al. Primer on medical decision analysis: Part 2— building a tree. Med Decis Making 1997;17:126 –35. Anderson RN. United States life tables, 1997. Natl Vital Stat Rep 1999;47:1–37. Javitt JC, Street DA, Tielsch JM, et al. National outcomes of cataract extraction. Retinal detachment and endophthalmitis after outpatient cataract surgery. Cataract Patients Outcomes Research Team. Ophthalmology 1994;101:100 –5; discussion 106. Javitt JC, Tielsch JM, Canner JK, et al. National outcomes of cataract extraction. Increased risk of retinal complications associated with Nd: YAG laser capsulotomy. The Cataract
41. 42.
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Patients Outcomes Research Team. Ophthalmology 1992;99: 1487–97; discussion 1497– 8. Kirschner CG, Davis SJ, Duffy T, et al. CPT 2000: Current Procedural Terminology 2000. Chicago: American Medical Association, 1999; pp 259 –272. Davis JB, ed. Medical Fees in the United States: Nationwide Charges for Medicine, Surgery, Laboratory, Radiology and Allied Health Services. Los Angeles: Practice Management Information Corp, 2000; pp 213–223. Diagnosis related groups. [cited 8/15/2000]. Available from URL: www.hfca.gov/stats. 2000 Drug Topics Red Book. Montvale, NJ: Medical Economics, 2000; pp 198, 398. Ross SA, Westerfield RW, Jordan BD. Fundamentals of Corporate Finance, 3rd ed. Chicago: Irwin, 1995, chap. 5, 112– 65. Damodaran A. Corporate Finance: Theory and Practice. New York: John Wiley & Sons, 1997; chap. 3, 37– 65. Laupacis A, Feeny D, Detsky AS, Tugwell PX. How attractive does a new technology have to be to warrant adoption and utilization? Tentative guidelines for using clinical and economic evaluations. CMAJ 1992;146:473– 81. Brown MM, Brown GC. Cost-effective analysis. The value component of evidence-based medicine. Evid Based Eye Care 2000;1:243–7. Kassirer JP. Adding insult to injury. Usurping patients’ prerogatives. N Engl J Med 1983;308:898 –901. Angell M. Patients’ preferences in randomized clinical trials [editorial]. New Engl J Med 1984;310:1385–7. Kassirer JP. Incorporating patients’ preferences into medical decisions [editorial]. New Engl J Med 1994;330:1895– 6. Brown GC, Brown MM, Sharma S. Difference between ophthalmologists’ and patients’ perceptions of quality of life associated with age-related macular degeneration. Can J Ophthalmol 2000;35:127–33. Schrader GD. Subjective and objective assessments of medical comorbidity in chronic depression. Psychother Psychosom 1997;66:258 – 60. Lunde IM. Patients’ perceptions—a shift in medical perspective. Scand J Prim Health Care 1993;11:98 –104. Brown MM, Brown GC, Sharma S, et al. Quality of life associated with unilateral and bilateral good vision. Ophthalmology 2001;108:643–7; discussion 647– 8. Press Release: World Health Report 2000. World Health Organization Assesses the World’s Health Systems [cited 7/15/ 00]. Available from URL: http://www.who.int/whr/2000/en/ pressrelease.htm. National Health Expenditures Projections.1998 –2008 [cited 8/15/00]. Available from URL: www.hcfa.gov/stats/ nhe%2Dproj/proj1998/proj1998pdf. Anesthesia Billing Guide [cited 4/15/01]. Available from URL: www.hgsa.com/professionals/bguides/anesthesia.shtml.
Discussion by George R. Beauchamp, MD The authors have demonstrated— using visual acuity outcome data, time-tradeoff utility values and computer-based economic modeling, and expressed as dollars per Quality Adjusted Life Years ($/QALY)—that cataract surgery performed in the initial eye with cataract is extremely cost-effective. The study provides useful methods and perspective to determine how resources may
From University of Texas Southwestern Medical Center, Dallas, Texas.
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be most effectively and appropriately applied across multiple services, diseases, procedures, and specialties. This important information emphasizes several core values. First, the generally accepted value of good sight is convincingly demonstrated in reference to the comparison of costs to benefits. The authors, concluding that quality ophthalmologic care is more valued by recipients than many (if not most) other medical services, have previously demonstrated that persons value sight more than most other functions. Second, the authors’ methods provide
Manuscript no. 200521.
1
Center for Evidence-Based Health Care Economics, Wills Eye Hospital, Jefferson Medical College, Philadelphia, Pennsylvania.
2
Retina Vascular Unit, Wills Eye Hospital, Jefferson Medical College, Philadelphia, Pennsylvania.
3
Cataract and Primary Eye Care Service, Wills Eye Hospital, Jefferson Medical College, Philadelphia, Pennsylvania.
4
Cost-Effective Ocular Health Policy Unit, Queens Medical College, Kingston, Ontario, Canada. Supported in part by the Retina Research and Development Foundation, Philadelphia, the Canadian Foundation for Innovation, Ottawa, Ontario, the E. A. Baker Foundation, the Canadian National Institute for the Blind, Toronto, Ontario, and the Premier’s Excellence Awards, Ontario Ministry of Science, Energy and Technology, Toronto, Ontario, Canada. Reprint requests to Melissa M. Brown, MD, MN, MBA, Center for Evidence-Based Health Care Economics, 1107 Bethlehem Pike, Suite 210, Flourtown, PA 19031.
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© 2002 by the American Academy of Ophthalmology Published by Elsevier Science Inc.
procedures in approximately a 2:1 ratio.1– 4 In the US patient cohort, 82.5% of patients were found to have a Snellen visual acuity equal to or greater than 20/30 at the 4 postoperative month end point.1 Complications of both phacoemulsification and extracapsular cataract extraction have also been well described in the past two decades. Along with the complication rates of the 772 patients entered in the US arm of the PORT study, many other researchers analyzed even larger numbers of patients and their complication rates after cataract surgery. Reported rates and outcomes of adverse events since cataract surgery have included posterior capsular opacification (PCO), endophthalmitis, cystoid macular edema, pseudophakic retinal detachment, lost lens fragments, lens dislocations, and pseudophakic bullous keratopathy.5–12 The numerous possibilities for visual outcome, with most patients finding an improvement in visual acuity, have led to many attempts to quantify the benefit of this elective surgery to the patient and society. Many studies have focused their measurements on the postoperative functioning of the patients.13–18 There has also been research on the issues of surgery on the second eye and the cost of cataract surgery to society.19 –21 Cost-utility analysis is a method that objectively measures the benefit derived from an intervention for the costs expended.22–31 It incorporates evidenced-based medicine and patient-based preferences (utility values) into a theoretical model accounting for the quality of a patient’s life in a ISSN 0161-6420/02/$–see front matter PII S0161-6420(01)00971-X
Busbee et al 䡠 Cost-effectiveness of Cataract Surgery particular health state. By the convention of utility theory, 1.0 in utility theory is equivalent to perfect health and 0.0 is equivalent to death.32–34 For example, a utility value approaching 1.0 is associated with excellent quality of life, encompassing factors such as the ability to perform activities of daily living and lack of anxiety related to the medical condition. Conversely, a patient-determined utility value approaching 0.0 is associated with a poor quality of life. Utility values recently have been used across medical specialties and theoretically allow for quantitative comparison among treatments in varied fields.17,28 –31 In the field of ophthalmology, utility values have been shown to be directly proportional to the Snellen visual acuity in the better-seeing eye. In a cohort of more than 300 consecutive patients, it has recently been shown that age, race, education, gender, socioeconomic status, length of time of disease, and the particular disease state itself did not alter the reproducibility of utility values correlated with different levels of visual acuity.35 In this study, utility values were incorporated into cost-utility analysis to evaluate the cost-effectiveness of initial cataract surgery.
Material and Methods Overview Decision analysis incorporating utility values was performed using software produced by Treeage, Inc., (Williamstown, MA).36 The clinical situation of cataract extraction with IOL implantation was simulated in the decision analysis tree.37 Because this study focused on the patient’s first cataract surgery and the procedure was definitive (i.e., recurrence rate of cataract is 0), Markov modeling was not used in this cohort. It was also assumed that the visual acuity in the fellow eye was equal to the preoperative vision in the eye undergoing cataract surgery. Visual acuity data in the fellow eyes were not reported by the PORT study. The microcomputer model performing decision analysis took into account the complications, as defined by the authors, and also the mortality within the group of patients. The median patient age in the PORT study was 73 years. This number was applied to current life tables to determine life expectancy.38
Cataract Extraction Patient Sample The patients from the US National Cataract PORT were studied to obtain visual acuity results in patients undergoing cataract extraction. The patients in the international arm of this collaboration were excluded from this study. These patients were excluded because of the fact that only in the US arm of the study did the procedure performed most closely resemble the standard of care in the US health care system. In this cohort of 722 US patients enrolled between July 1991 and December 1991, phacoemulsification was performed on 67.3% of the patients. In Canada, Denmark, and Spain the rates of phacoemulsification during the same period were to 63%, 33%, and 2%, respectively.1 The PORT cohort of patients had an end point of 4 months since cataract surgery. The authors recognize that the complications of endophthalmitis, macular edema, and lost lens fragments typically occur within this 4-month window. The visual sequelae in eyes with these complications are therefore included in the PORT 4-month data. Thus, the decision analysis tree to simulate visual acuity results over the lifetime of the patient excludes
endophthalmitis, macular edema, and lost lens fragments in determining visual results (Fig 1). A synthesis of large studies, totaling more than 58,000 patients, shows similar complication rates among these studies and the PORT study.1,5,6,9 –12
Cataract Extraction Complication Rates and Visual Results PCO. The rate of 28% over 5 years was used for PCO following cataract extraction.6 The mean time of treatment after surgery was assumed to be 2 years.6 An increased rate of retinal detachment after treatment of the PCO by yttrium–aluminum– garnet (YAG) capsulotomy was included in the visual results. Javitt et al39,40 reported a 3.9-fold increase in the cumulative retinal detachment rate of 0.81% after cataract surgery. The authors made the assumption that visual acuity returned to postoperative baseline after YAG capsulotomy in the 96.8% of patients who did not experience the complication of retinal detachment. Endophthalmitis. The PORT study only had one patient in the cohort who developed postoperative endophthalmitis.2 The authors believe this is an accurate outcome because of size of the patient cohort. The endophthalmitis rate used in this study was 0.13%.9 The visual result of this is included in the mean, 4-month postoperative visual acuity. Lens Dislocation. The rate of 1.1% was used for lens dislocation after cataract extraction.9 The visual result since IOL repositioning, exchange, or removal was derived from a weighted average of slightly better than 20/50 from Mello et al.5 Cystoid Macular Edema. The PORT study observed postoperative ophthalmoscopic cystoid macular edema in 3.21% of patients.2 The visual result from this complication was included in the mean 4-month postoperative visual acuity. Pseudophakic Bullous Keratopathy. The rate of 0.3% was used for pseudophakic bullous keratopathy after cataract surgery.9 The resultant visual acuities were derived from a weighted average from Cohen et al.10 This visual acuity of 20/85 corresponded to a utility value of 0.70 in the 70.7% of patients who underwent penetrating keratoplasty. The surgical treatment of pseudophakic bullous keratopathy was assumed to occur 1 year after cataract surgery. The visual acuity of counting fingers in the 30.3% of patients who did not have surgery corresponded to a utility value of 0.52.10,35 The medical costs for this treatment were assumed to occur over the lifetime of the patient. The utility value used for nonsurgical pseudophakic bullous keratopathy was equivalent to that of patients who received penetrating keratoplasty when applied to the Markov model, however. This assumption was made, because counting fingers vision would most likely correspond to the worse-seeing eye. Therefore, the same utility value of 0.70 was used for patients treated with medical therapy. Lost Lens Fragments. In the PORT study, 0.28% of patients who underwent cataract extraction experienced lost nuclear material in the vitreous.2 The visual result of this was included in the mean 4-month postoperative visual acuity. Retinal Detachment. The rate of 0.81% was used for retinal detachment after cataract surgery.38 The mean time of retinal detachment repair was assumed to occur a year after cataract surgery, unless a YAG capsulotomy was performed, in which case retinal detachment was assumed to occur 1 year after the capsulotomy. The resultant visual acuity of slightly worse than 20/70 was derived from a weighted average reported in the publication by Greven et al.12
Conversion of Visual Acuity to Utility Values A patient preference– based, time tradeoff method was used to derive utility values associated with the best-corrected visual acu-
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Figure 1. Decision analysis tree for cataract management. Utility values are located to the right of the decision nodes (triangles). The incidence of events are shown below the arms in the tree. (IOL ⫽ intraocular lens).
ity in the better-seeing eye. Essentially, this is a method by which the patient determines what quantity of time they would be willing to relinquish to have quality of life associated with 20/20 vision. This method of utility measurement has been thoroughly described in the literature.22–27,35 The utility value corresponding to the mean 4-month postoperative visual acuity of 20/27 after cataract extraction is 0.86.1,35 The utility values corresponding to the complications associated with cataract extraction are listed in Table 1.
Medical Costs The health care costs arising from provider services were according to year 2000 Current Procedural Terminology data and the payments by the Health Care Finance Agency in nominal US dollars.41 These payments set by the Health Care Finance Agency take into account the factors of physician work, practice expense, and malpractice expense.42 Any institutional costs incurred as a result of the procedures or admissions related to cataract surgery or its complications were categorized into one of two groups. For ambulatory procedures, the Medicare 2000 outpatient facility fee of $928 was used in this study.43 The second group consisted of inpatient operating room costs and admission, which related to retinal procedures in this study. The diagnosis-related group #36 fee of $2825 was representative of these procedures.43 Costs related to drug expenditures were taken from the average
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wholesale prices as defined in the 2000 Drug Topics Red Book.44 The medications that were included in this study consisted of topical antibiotics, topical steroids and nonsteroids, and topical cycloplegics. The costs and applicable current procedural terminology codes for each procedure are summarized in Table 2. In many clinical scenarios, there is more than one treatment option for a given complication of cataract surgery. For each of these complications, an estimated percentage of patients receiving Table 1. Utility Values Associated with the Treatment of the Complications after Cataract Surgery Complication
Utility Value35
Posterior capsular opacification—no complications Posterior capsular opacification—with complicating RD Endophthalmitis Lens dislocation Cystoid macular edema Pseudophakic bullous keratopathy—treatment with PK Pseudophakic bullous keratopathy—medical treatment Lost lens fragments Retinal detachment
0.86 0.73 NA 0.85 NA 0.70 0.70 NA 0.73
NA ⫽ not applicable, since accounted for in 4-month PORT study data1; PK ⫽ penetrating keratoplasty; RD ⫽ retinal detachment.
Busbee et al 䡠 Cost-effectiveness of Cataract Surgery each treatment option was determined. This allowed for the most accurate assessment, using a weighted average, of the total costs. Each complication and its treatment options are described in the following.: PCO. YAG capsulotomy was the only procedure used to treat this complication. In addition, no facility fee was applied because YAG laser is typically an office-based procedure. Endophthalmitis. Vitreous tap and injection accounted for 80% of endophthalmitis patients in this model. The remaining 20% of patients were assigned to the vitrectomy group.45 Lens Dislocation. IOL repositioning or exchange with accompanying pars plana vitrectomy accounted for 11% of patients with lens dislocation in this model. The remaining 89% of patients had IOL repositioning or exchange alone.5 Cystoid Macular Edema. All patients with this complication incurred treatment costs relating to both topical nonsteroidal (ketorolac) and steroidal medications. Pseudophakic Bullous Keratopathy. Penetrating keratoplasty was the treatment option used for 70% of the patients with pseudophakic bullous keratopathy.10 The remaining 30% of patients incurred treatment costs related to lifetime use of topical 5% sodium chloride solution. Lost Lens Fragments. All patients with this complication incurred treatment costs related to a pars plana vitrectomy and retrieval of the lens fragments. Retinal Detachment. A scleral buckling procedure was the treatment option used for 50% of patients with pseudophakic retinal detachment. The remaining half of patients incurred the costs related to a retinal detachment repair with vitrectomy (personal communication, GC Brown on the practice patterns of the Retina Service at Wills Eye Hospital, August 2000).
Present Value Analysis The initial outlay of dollars for the preceding expenditures was assumed to occur at the initiation of therapy. The treatment effect gained from those dollars remains over the lifetime of the patients. Thus, discounting was used to account for the time value of money26,45,46 The annual discount rate used in this study was 3% for both costs and health benefits (quality-adjusted life-years [QALYs] gained).
Results A resultant, mean utility value of 0.858 was obtained using decision analysis for patients undergoing initial cataract surgery. This value takes into account the risks and deleterious effects of complications over the remainder of the patient’s life. For patients who did not undergo cataract surgery over their lifetime, a utility value of 0.71 was assigned. This corresponded to the mean preoperative visual acuity of 20/83 found in the PORT study.1 The net utility gain for initial cataract surgery was thus 0.148. The decision tree used to calculate the number of QALYs gained is shown in Figure 1. A life expectancy of 12 remaining years in this cohort, multiplied by the net utility gain, resulted in 1.776 QALYs gained by cataract surgery.38 Cataract surgery and its related expenditures for complications resulted in a total health care cost of $2525. This encompassed the costs of complications that were included in the 4-month postoperative data, as well as those (i.e., retinal detachment, corneal edema) occurring after 4 months. Present value analysis was accounted for by discounting the initial benefit of the intervention, or 1.776 QALYs gained. By incorporating a 3% annual discounting rate, the final number of QALYs gained from the procedures, over the remaining lifetime of the patient, was 1.25.
The resultant cost-effectiveness (dollars spent per quality-adjusted life-years [$/QALY]) gained from initial cataract surgery was found to be $2020.
Sensitivity Analysis One-way sensitivity analysis was performed varying costs, utility values, and the discount rate. When the total costs were increased by 25%, the $/QALY gained was $2525, whereas decreasing costs by 25% yielded a $/QALY gained of $1515. Raising all utility values by 25% yielded a $/QALY gained of $1605, whereas lowering them by 25% yielded a $/QALY gained of $2703. Varying the yearly discount rate resulted in a $/QALY gained of $1432 for a 0% rate, $2544 for a 5% rate, and $4398 for a 10% rate.
Discussion The data presented herein suggest that cataract surgery with IOL implantation is a very cost-effective intervention using conventional standards. Although the standards for costeffectiveness in health care vary from one society to another, depending on the resources that society has to expend, it has been suggested that interventions costing less than $20,000/QALY gained are highly cost-effective, whereas those costing more than $100,000/QALY are not cost-effective.47 With a cost-effectiveness of $2020/QALY gained, cataract surgery falls well within the very costeffective range. Compared with other interventions in ophthalmology, the cost-effectiveness of cataract surgery in year 2000, US real dollars is roughly comparable to that of cryotherapy for threshold retinopathy of prematurity at approximately $1900/QALY gained.25 It is less cost-effective than laser therapy for threshold retinopathy of prematurity at about $700/QALY gained25 but more cost-effective than laser treatment for choroidal neovascularization at approximately $5000/QALY gained.23,24 It is substantially much more cost-effective than the treatment of acute central retinal artery obstruction at about $6 million/QALY gained.48 Concerning nonophthalmologic specialties,35 single-vessel coronary artery bypass surgery for disease of the left anterior descending artery costs approximately $7000/ QALY gained, whereas treatment of systemic arterial hypertension (diastolic, 95–104 mmHg in males, aged 40) costs approximately $58,000/QALY gained, and ambulatory peritoneal dialysis approximately $90,000/QALY gained. Thus, it can be seen that the cost-effectiveness of cataract surgery compares favorably with these commonly performed interventions performed in nonophthalmologic specialties. It should be emphasized that the value gained from cataract surgery in this article is based on patient preferences, or what patients believe are most valuable to them. There is a growing body of literature suggesting that perceptions of value from the patient’s point of view are critical for improving our health care system.49 –51 The authors herein concur that the preferences of patients who experience a health state firsthand are the most valid. It should also be noted that the preferences and values of patients with a health state can differ substantially from those of surrogate
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Ophthalmology Volume 109, Number 3, March 2002 Table 2. Medical Costs (Year 2000 Nominal US Dollars) and Current Procedural Terminology Codes
Service
Current Procedural Terminology Discounted Code41 Cost42
Cataract surgery Initial office consultation A-scan with IOL calculation Cataract extraction Ambulatory surgical center fee Postoperative medications Anesthesia fees58
99254 76519 66984 NA NA NA
$144 $79 $748 $928 $54 $360 Total $2313
Posterior capsular opacification YAG capsulotomy Postlaser medications
66821 NA
$184 $22 Total $206
Endophthalmitis—tap and inject Initial office consultation Vitreous tap Vitreous drug injection Postprocedure medications
99254 67010 67028 NA
$144 $476 $158.50* $63.44 Total $841.94
99254 67036 67028 DRG #3643 NA NA
$144 $870 $158.50* $2825 $63.44 $648 Total $4708.94
66825 NA NA NA
$626 $928 $63.11 $360 Total $1977.11
Endophthalmitis—pars plana vitrectomy Initial office consultation Pars plana vitrectomy Vitreous drug injection Inpatient facility fee Postoperative medications Anesthesia fees58 IOL dislocation IOL repositioning Ambulatory surgical center fee Postoperative medications1–4 Anesthesia fees58
IOL dislocation with pars plana vitrectomy Initial office consultation 99254 Pars plana vitrectomy 67036 IOL repositioning 66825 Inpatient facility fee DRG #3643 Postoperative medications1–3 NA Anesthesia fees58 NA Cystoid macular edema Topical medications3,4
NA
$144 $870 $313* $2825 $63.11 $648 Total $4863.11 $152 Total $152
Pseudophakic bullous keratopathy—surgical Initial office consultation Penetrating keratoplasty Ambulatory surgical center fee Postoperative medications1–3 Anesthesia fees58
99254 65730 NA NA NA
$140 $1062 $901 $61.27 $629 Total $2793.27
Pseudophakic bullous keratopathy—medical Lifetime topical medication5
NA
$1319.08 Total $1319.08
Lost lens fragments Initial office consultation Pars plana vitrectomy Inpatient facility fee Postoperative medications1–3 Anesthesia fees58
99254 67036 DRG #36 NA NA
$144 $870 $2825 $63.11 $648 Total $4550.11
Retinal detachment—scleral buckle Initial office consultation RD repair—scleral buckle Inpatient facility fee
99254 67107 DRG #36
$140 $1091 $2743 (continues)
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Table 2. (continued)
Service
Current Procedural Terminology Code41
Postoperative medications1–3 Anesthesia fees58
NA NA
$61.27 $629.00 Total $4664.27
Retinal detachment—vitrectomy Initial office consultation RD repair—vitrectomy Inpatient facility fee Postoperative medications1–3 Anesthesia fees58
99254 67108 DRG #36 NA NA
$140.00 $1518.00 $2743.00 $61.27 $629.00 Total $5091.27
Discounted Cost42
*Only 50% of the second procedure is included as per Medicare guidelines. IOL ⫽ intraocular lens; 1 ⫽ one 5ml bottle of prednisolone acetate drops; 2 ⫽ one 5ml bottle of atropine drops; 3 ⫽ one 5ml bottle of ciprofloxacin drops; 4 ⫽ two 5ml bottles of ketorolac drops; 5 ⫽ 125 5ml bottles of 5% sodium chloride solution (estimated lifetime supply); CPT ⫽ current procedural technology; DRG ⫽ diagnosis-related group; NA ⫽ not applicable; RD ⫽ retinal detachment; YAG ⫽ yttrium–aluminium– garnet.
responders such physicians, administrators, and the general public.52–54 For this additional reason, it was elected to use patient preferences for this study. Of importance is the fact that this article deals with cataract surgery in the first eye. The cost-effectiveness of cataract surgery in the second eye, which has not been addressed herein, is the subject of another article. Cataract surgery in the second eye is likely to be very cost-effective as well, because the utility values of ophthalmic patients with good vision in two eyes are substantially higher than those of patients with good vision in one eye.55 The substantial worry about the welfare of the good eye in patients who have good vision in only one eye is believed to be a major factor contributing to this utility difference. The cost-utility analysis used herein allows a comparison across all medical specialties of the value received from health care interventions for the dollars expended. Critically, it incorporates an objective measure of the patientperceived improvement in quality of life (as well as the improvement in length of life for select cases) conferred by an intervention. The authors are unaware of another method that allows this type of comparison. The United States has recently been ranked as No. 37 in health care quality in the world by the World Health Organization, which used a method heavily weighted toward the efficient use of medical resources a given society has available.56 Cost-utility analysis provides a potential information system that can help to improve the efficient use of medical resources and improve the quality of medical care at the same time.55 As with any study, there are potential inherent weaknesses in this analysis. The authors acknowledge that typical practice patterns for cataract extraction dictate surgery on the eye with an equal or worse visual acuity. A weakness of this study resides in the assumption that the preoperative visual acuity of the fellow eye was equal to the operated eye in all patients. This assumption had to be made for the model because of a lack of data on preoperative, fellow eye
Busbee et al 䡠 Cost-effectiveness of Cataract Surgery visual acuities in large, prospective cataract extraction studies, including the PORT study. A scenario that potentially would decrease the margin of benefit between the operated and unoperated eye is if the unoperated eye had a preoperative visual acuity substantially better than the preoperative cataract eye. For example, assume cataract surgery was planned in an eye with visual acuity of 20/60, and the fellow eye had a visual acuity of 20/30. Even by performing surgery on the worse eye, the initial utility change would be less substantial than depicted in our model. This is because utility values are derived from the better-seeing eye. Therefore, the preoperative utility value would correspond to 20/30 (fellow eye) and postoperatively to 20/27 (operated eye). This smaller difference, however, would approach the utility change in our study over time because of the expected decline of vision in the fellow eye with the remaining cataract. The authors believe the model presented in this article accurately depicts a generalized clinical scenario for cataract surgery. Additional weaknesses in this study include the incomplete analysis of all the incremental costs of cataract surgery, or those induced by performing the surgery, versus no treatment. The societal costs saved by performing cataract surgery were not included in this analysis. Also, the utility values used in our study were not specifically obtained from patients with cataract, but rather visual loss in general. Many of the patients used to gather original utility data35 had irreversible retinal diseases. This possibly overestimates the value of visual change, because patients who are aware their vision cannot improve might put more value on regaining that vision. It has been shown, nonetheless, that the degree of visual loss itself, rather than the underlying cause, is most closely correlated with utility values.35 To further counter criticism in this regard, altering the utility values by as much as 25% with sensitivity analysis failed to substantially alter the cost-effectiveness of the cataract surgery. There may also be criticism of the concept of costutility analysis in general, but then it must be asked, “What is the preferable alternative?” With an annual health care budget in the United States consuming 14% of the gross domestic product in 2000, and projected to increase to 16.2% of the gross domestic product by the year 2008,57 potential solutions, such as cost-utility analysis, to restrain costs and improve quality of care are highly desirable.55 In summary, cataract surgery in the United States seems to be a very cost-effective intervention by conventional standards. Likely factors that contribute to this are the clinical effectiveness of the surgery, the substantial improvement in patient-perceived quality of life it confers, and the reasonable cost made possible by technological advances and the ingenuity of those involved in the evolution of the procedure.
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Discussion by George R. Beauchamp, MD The authors have demonstrated— using visual acuity outcome data, time-tradeoff utility values and computer-based economic modeling, and expressed as dollars per Quality Adjusted Life Years ($/QALY)—that cataract surgery performed in the initial eye with cataract is extremely cost-effective. The study provides useful methods and perspective to determine how resources may
From University of Texas Southwestern Medical Center, Dallas, Texas.
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be most effectively and appropriately applied across multiple services, diseases, procedures, and specialties. This important information emphasizes several core values. First, the generally accepted value of good sight is convincingly demonstrated in reference to the comparison of costs to benefits. The authors, concluding that quality ophthalmologic care is more valued by recipients than many (if not most) other medical services, have previously demonstrated that persons value sight more than most other functions. Second, the authors’ methods provide