GERIATRIC UROLITHIASIS

~022-5347/97/1586-2221$03.00/0 Vol. 158. 2221-2224, December 1997 Printed in U.S.A.

THE JOKKNAL OF UROLOGY

Copyright @ 1997 by &ERICAN

UROLCGICAL ASSOCIATION,

INC

GERIATRIC UROLITHIASIS DONALD L. GENTLE, MARSHALL L. STOLLER,* JEREMY E. BRUCE

AND

STEPHEN W. LESLIE

From the Department of Urology, University of California School of Medicine, San Francisco, California, and b r a i n , Ohio

ABSTRACT

Purpose: We define the differences between geriatric patients with urinary stone disease compared t o a younger cohort. Materials and Methods: A data base, including serum biochemical profiles, 24-hour urinalyses and standardized questionnaires, was retrospectively evaluated from more than 6,000 consecutive patients with urinary stone disease. Results: Geriatric stone formers comprised 12% (721) of all stone patients. Two-thirds of these elderly patients had aberrant urinary values and 29% had isolated hypocitraturia compared to 17% in the younger group. Of geriatric stone forming patients 76%had recurrent urinary stones (mean 3.5 stone episodes), which was similar to the younger comparable group (77%, mean 3.3 stone episodes). The severity of urinary stone disease was similar between the 2 groups based on the need for urological intervention. Geriatric stone patients, in general, experienced the first stone episode later in life (after age 50 years) compared with younger patients. Elderly patients had a n increased incidence of uric acid stones, but had a similar incidence of struvite calculi. Geriatric stone patients underwent parathyroid surgery more frequently (2.7 versus 0.7%).Geriatric stone forming patients rarely had renal failure. Conclusions: The incidence, recurrence and severity of recurrent urinary stone disease were similar between geriatric and younger stone forming patients. Geriatric stone patients had a n increased incidence of isolated hypocitraturia, uric acid calculi and previous parathyroidectomy. The geriatric stone population is not merely a n extension of younger stone forming patients presenting a t an older age. Rather, geriatric patients commonly experience the first symptomatic stone episode later in life. KEY WORDS:metabolic diseases, geriatrics, urinary calculi

Urinary stone disease affects 5 to 10% of the American population.' Patients with urolithiasis have significant recurrence rates, approximately 50% in the first 5 years2 Data regarding geriatric urinary stone disease are sparse. It has been suggested that elderly patients may be more prone to have urinary stones.:' Previous epidemiological analyses estimated the annual incidence of urinary stones in geriatric patients (after age 65 years) to be 2%.4 Outpatient data have demonstrated a decreasing incidence of urinary stone diagnoses with increasing age (2.3 stones/1,000 outpatient visits between ages 30 to 59 years, 1.9/1,000 between ages 60 to 69 Years and 1.1/1,000 after age 70 yearsL5 Urolithiasis hospital admissions during a 5-year period decreased with increasing age.5 Overall, the incidence of geriatric urinary stone disease appears t o be between 0.1 and 270,and there is no evidence of an increased incidence of urinary stones with Metabolic abnormalities associated with urinary stone disease are well documented. Factors predisposing elderly patients to nephrolithiasis are thought to be similar t o any Patient with urinary stone disease. The incidence of metabolic defects in geriatric patients with urolithiasis has been poorly documented. We define metabolic defects associated with geriatric urinary stone disease and identify any unique chical presentations compared to a younger cohort of stone forming patients. MATERIALS A N D METHODS

A multi-institutional data base of more than 6,000 consecutive patients referred for urinary stone disease was retrosPectively evaluated by standardized questionnaires, serum Of

biochemical profiles and 24-hour urinalyses. A geriatric subpopulation was defined by age greater than 65 years. Data from all patients who were referred for urinary stone disease were analyzed for serum and urinary metabolic parameters. Patients with incomplete or inadequate data were excluded from the study. Urinary metabolic abnormalities were categorized into solitary or combined urinary defects. Combined urinary abnormalities included any combination of hypercalciuria (greater than 250 mg./24 hours), hypocitraturia (less than 320 mg./24 hours), hyperoxaluria (greater than 40 mg./24 hours) and/or hyperuricosuria (greater than 600 mg./24 hours). The 24-hour urinalyses were collected in a standard fashion. Voided urine was collected and refrigerated for 2 consecutive 24-hour intervals, the voided urinary volume was recorded, and an aliquot sample was obtained and evaluated a t a single facility with accepted normal ranges and controls. Evaluation of our geriatric population was compared to our younger cohort of stone forming patients. Statistical evaluation was performed with the Student t test and analysis of variance determinations. RE S U1.T S

Geriatric stone formers comprised 124 (721) of 5,942 patients. The mean age of elderly patients was 71 years (range 65 to 89). The mean weight of elderly patients was 78 versus 82 kg. for the younger stone forming population (p <0.0001, table 1). Geriatric stone formers had a male predominance of 71% (512 of 721) versus 65% (3,394 of 5,221) for the younger cohort. The ethnicity of our study population was unknown. Geriatric patients reported a mean of 3.5 total stone episodes with no statistical differences compared to our younger cohort (table 1). The risk of multiple urinary stone recurrences was similar between geriatric stone forming patients

S\ccepted for publication May 29, 1997. Requests for reprints: Department of Urology, U-575. University Cahfornia. San Francisco, California 94143-0738. 2221

2222

GERIATRIC UROLITHIASIS TABLE 1. Population demographics Age After 65 Yrs.*

AgeBefore* 65

Or

43 3 (114.43 61 70 8 (4 3,69 8 ) Age 81 5 i 1 9 0 . 8 1 01 Wt I k g 1 77 9 ( 1 4 4 . 7 7 01 3 3 (2 3 , 3 01 Recurrent stone 3 5 ( 2 5 . 3 01 disease * Values are expressed as mean \SD. median)

p Value


and the younger comparable group (76 versus 77%). Patients who required a single endourological manipulation and those requiring multiple procedures were similar between the 2 groups (geriatric 21 and 14%, younger 25 and l l % , respectively). Of the geriatric group 92% never required percutaneous nephrolithotomy, which was similar to the younger group (94%). Of those patients undergoing percutaneous nephrolithotomy the need for a single procedure was similar between the 2 groups (geriatric 6% versus younger 4%). Of the geriatric patients 2% required multiple staged percutaneous stone procedures, which was similar to the younger group (2%).Shock wave lithotripsy was required in 4 6 8 of elderly patients versus 37% in the younger group (p <0.0001). Geriatric patients who required 1 or 2 shock wave lithotripsy procedures (26% or 11%) was similar to the younger group (23% or 8%). Overall, geriatric and younger patients had similar rates of intervention for symptomatic urinary stones. The severity of urinary stone disease was similar between the 2 groups. Urinary and serum biochemical data from the geriatric stone population are summarized in table 2. Statistical differences (p <0.0001) between the geriatric population and the younger cohort were identified for mean serum parathormone, 1,25-hydroxyvitamin D, creatinine and glucose, and for mean urinary calcium, citrate, sodium, uric acid, and creatinine clearance (table 2). Mean 24-hour urinary voided volumes were similar between the 2 groups (geriatric stone formers 1,654 ml. daily, younger population 1,633 ml. daily) Geriatric stone patients rarely had renal failure requiring dialysis or renal transplantation which was similar to the TABLE2 . Serum chemistries and urinary metabolic evaluations Age After 65 Yrs.*

Age 65 Yrs. or Before*

Value

Serum chemistry: 24.8 (4.5) Not significant 25.2 (3.81 Bicarbonate Immol.A.) 9.7 (0.5) Not significant 9.7 10.51 Calcium (mgJdl.) 5.2 10.3) Not significant 5.2 10.3) Ionized calcium (mmo1.A.) 104.8 13.2) Not significant Chloride (rnmolA.) 105 (3.11 1.6 (0.2) Not significant 1.6 10.2) Magnesium tmg./dl.) 36.3 (25.3) <0.0001 43.9 (36.5) Parathormone (ng.A.1 3.3 (4.1) Not significant Phosphorus (mg./dl.) 3.2 (0.6) 4.3 (0.41 Not significant 4.4 (0.4) Potassium (rnmo1.A.) 41 (15.01 <0.0001 37.4 (13.7) 1.25-Hydroxyvitamin D (ng.A.) 5.0 (1.5) Not significant 5.1 (1.5) Uric acid !mg./dl.) 1.04 (0.2) <0.0001 1.18 10.3) Creatinine lmg./dl.l 140.7 (2.8) Not significant Sodium (mmo1.A.) 141.3 (2.8) 99.2 (30.4) <0.0001 109.5 (36.7) Glucose (mgJdl.) Urinary metabolic evaluations: 171 (103) Calcium (mg. daily) 213 (118) <0.0001 Citrate (mg. daily, 521 (310) <0.0001 462 (313) (39) <0.001 Magnesium (mg. daily) 77 (39) 83 32.1 (191 Not significant Oxalate (mg. daily) 298 (145) 937 14161 <0.0001 Phosphate (mg. daily) 800 (353) Sodium (mEq. daily) 151 1641 171 182) <0.0001 Sulfate (mmol. daily) 38.8 119) <0.0001 3 2 5 (1491 (254) <0.0001 Uric acid (mg. daily) (2051 557 430 6 01 ( 0 77) 6.02 10.68) Not significant Urine pH 17701 Not significant Val. (ml. daily) 1.654 (678) 1,633 96.6 (36.61 <0.0001 Creatinine clearance 702 (265) (m1.lmin.1 40.2 148.6) Not significant Cystine lmg. daily) 3 6 1 (2661 Protein (me. dailvl 141 14091 Not sienificant 185 1395) * Values are expressed as mean (SD). Y~

younger group (0.1 versus 0.04%). There was a significant difference between geriatric patients who had undergone parathyroid surgery compared to the younger population ( 2.7 versus 0.7, p <0.0001). The 24-hour urinary metabolic abnormalities were categorized into isolatedlsolitary or combined urinary defects. Hypocitraturia alone (29%) was the most common abnormal urinary value in the geriatric stone population. Hypercalciuria alone occurred in 10%. with low incidences of isolated hyperoxaluria and isolated hyperuricosuria ( 6 and 3p+,respectively, table 3). Of the geriatric stone forming group 48% had a solitary urinary metabolic defect and 63% had 1 or more urinary metabolic abnormalities and of the younger stone forming patients 68% had 1or more 24-hour metabolic defects (table 3). Calculi retrieved from elderly patients were composed primarily of calcium oxalate (74% monohydrate and dihydrate). Uric acid stones occurred in 11% of geriatric patients, whereas the incidence of calcium phosphate calculi was lower (6%). Mixed chemical compositions of urinary stones were common. Calcium oxalate and uric acid was the most frequent combined stone composition (7%). Other stones (cystine, struvite and triamterene) were rare in the elderly population (table 4). Urinary stones were not retrieved in 54% of elderly patients. The predominant stone composition (84V) in our younger stone patients was calcium oxalate (monohydrate and dihydrate). Uric acid stones occurred less frequently (5%) in the younger group compared to the geriatric stone formers. Calcium phosphate stones were similar (4%) in the younger stone forming group, with rare cystine and struvite stones. Mixed stone compositions (calcium oxalate and uric acid) were similar (7%) in our younger cohort. Urinary stones were not retrieved in 44% of the younger group of patients. Urinary pH of 5.5 or less in geriatric patients was similar to younger patients (32 versus 28%). Elderly stone patients with a history of gout had higher mean serum and urinary uric acid values compared with geriatric stone patients without gout (gout 6.7 mg./dl. and 543 mg. daily, nongout 5.0 mg./dl. and 429 mg. daily). Geriatric stone patients with gout had a slightly decreased mean urinary pH level compared to nongout patients (5.8 versus 6.0). A history of gout was similar between the geriatric and younger patients ( 1.3 versus 1.5%). Approximately 40% of geriatric stone forming patients experienced the first symptomatic urinary stone episode before age 50 years. In contrast, 90% of our younger patients experienced the first stone episode before age 50 years. Of elderly patients 10% presented with the first stone event late in life (after age 70 years). The first stone episode was similar for both age groups for the middle age range of 41 to 50 years

TABLE3. Urinary metabolic defects ~

Urinary Metabolic Defect Hypercalciuria: Alone Combined defect Hypocitraturia: Alone Combined defect Hyperoxaluria: Alone Combined defect Hyperuricosuria: Alone Combined defect No urinary metabolic defect Any urinary defect Any solitary defect A n y combined defect

Y

~~

--

S Geriatric Stone

',i Younger Stone

Pts.

Pts

10 7

12 18

29 7

17 10

6 11

16

I

6 37

8 16 32

63 49 13-

68 42 26

3

GERIATRIC UROLITHIASIS TABLE4. Stone cornnosition

2223

wthritis will form uric acid stones, and 40% of patients with uric acid calculi will later have gouty arthritis.12.13 Urinary Stone Composition Geriatric Stones Younger Stones 1pH less than 5.5 may be the most important determinant of uric acid stone formation in contrast to hyperuricosuria, hy74 84 Calcium oxalate (monohydrate and dihydrate) peruricemia or history of gout.12 Uric acid stones were more 5 11 Uric acid common in our geriatric population despite a similar mean 7 7 Calciuduric acid urinary pH and urinary uric acid excretion. The incidence of 6 4 Calcium phosphate geriatric stone patients who had a history of gout was similar Less than 1 Less than 1 Cystine Less than 1 Less than 1 to our younger group. Elderly stone patients with gout had Struvite Less than 1 0 Triamterene higher mean serum and urinary uric acid values, and lower urinary pH levels compared to geriatric stone patients without gout. These conditions may promote uric acid stone formation. (geriatric 16%, younger 19%).In general, geriatric patients Several metabolic differences for urinary stone disease experienced the first symptomatic stone episode at a later were identified when comparing geriatric stone patients to a age compared t o the younger stone forming population. younger cohort. Mean parathyroid hormone levels were significantly increased, and serum 1,25-hydroxyvitamin D was DISCUSSION decreased in the geriatric subgroup. Severe vitamin D defiGeriatric patients comprised 12% (721 patients) of more ciency with resulting secondary hyperparathyroidism has than 6,000 patients referred and evaluated for urinary stone been demonstrated in elderly nursing home patients, and disease. Mhiri et a1 followed all patients referred for urinary may be common in many geriatric patients.l4.I5 Genetic facstones during a 10-year period, and identified 174 geriatric tors, chronic parathyroid stimulation, chronic thiazides or patients (10% of total patienM.6 Thus, the incidence of geri- lithium use and vitamin D deficiency may initiate hyperparaatric urolithiasis appears to be 10 to 12% of all patients thyroidism.16 The number of geriatric patients who required parathyroid referred for urinary stone disease. The 24-hour urinalyses revealed several differences be- surgery was higher compared to the younger population. tween the geriatric and younger groups. Creatinine clearance Primary hyperparathyroidism has not been described to inwas decreased and mean serum creatinine increased in our crease with age. The incidence of primary and secondary elderly stone population. However, geriatric patients did not hyperparathyroidism ranges between 0.1 and 0.4%, which have a higher incidence of renal failure compared to the increases to 1.3% in elderly women secondary to estrogen younger group. Elderly patients with recurrent urinary deficiency at menopause.l7 Presently, hyperparathyroidism stones typically did not progress to dialysis or renal trans- may be more commonly diagnosed as a result of routine plantation. Both age groups had a similar recurrence rate serum biochemical screening of the population.17 Of patients and severity of urinary stone disease. Urinary volume was with primary hyperparathyroidism 3 to 13% experience urinot an age related factor for urinary stone disease, since both nary stones as the first clinical presentation.18 Treatment of groups had similar mean urinary volumes (approximately primary hyperparathyroidism is surgical. Geriatric patients 1,600 ml. daily). Urinary voided volumes from our study tolerate parathyroid surgery well, which commonly normalpopulation were similar to urinary volumes obtained from izes the hypercalcemia. 16.19 Geriatric patients may require parathyroid surgery for symptomatic hypercalcemia or bone stone forming and control patients (1,350 ml. daily).7 Of our elderly patients 63% had 1or more 24-hour urinary disease, in comparison to younger patients who usually reabnormalities. Approximately 50% of geriatric patients had quire parathyroidectomy for urinary stone disease.16-18 A an isolated urinary metabolic defect and isolated hypocitra- higher percentage of our geriatric stone patients underwent turia was most common (29%)in the geriatric stone forming parathyroid surgery compared to our younger group, and this group. Hypocitraturia may be more common in geriatric pa- may reflect an age related increase in the diagnosis of hypertients due to a mild, physiological metabolic acidosis that parathyroidism. The differentiation between parathyroidecdevelops from an age dependent decline in renal function. tomy for urinary stone disease compared to other indications Renal function has been shown to decrease progressively (hypercalcemiahone pain) was not ascertained. The 3 additional factors that may increase urinary stone with age.8 Frassetto et a1 investigated the effects of age, glomerular filtration rate, net renal acid excretion and blood formation in geriatric patients are increased urinary tract carbon dioxide partial pressure on the acid base balance in 64 infections, diminished ambulatory mobility and increased healthy adults (age 17 to 74 years) while ingesting controlled crystalluria. Urinary tract infections occur more commonly diets.9 The age dependent decline in renal function was in elderly patients. Nordenstam et a1 found no difference in shown to cause a low grade, dietary dependent metabolic the incidence of geriatric patients with stones who died with acidosis and the severity of the acidosis increased with age bacteriuria compared to those who survived.”J However, the (with a constant endogenous acid produ~tion).~ Thus, hypoci- incidence of stone disease in their geriatric population was traturia in our geriatric stone population may result from an not identified. Only 1% of urinary stones was composed of age related decline in renal function resulting in a low grade, struvite in our geriatric population, which was similar to our subclinical metabolic acidosis. These age dependent physlo- younger cohort. Although elderly patients are at increased logical changes were identified clinically in our geriatric pop- risk for urinary tract infections andor bacteriuria, the etiolh i o n as similar urinary pH and serum bicarbonate, in- ogy is rarely due to infectious renal calculi. Decreased ambulation in geriatric patients may increase creased serum creatinine, decreased creatinine clearance bone resorption and urinary calcium excretion, which may and a higher incidence of isolated hypocitraturia. Urinary stone compositions were similar between the ge- potentiate urinary stone formation. However, an increased riatric stone patients and our younger cohort. Calcium OX- incidence of hypercalciuria, was not seen in our elderly stone stones were predominant (geriatric 748, younger 84%). population compared to our younger group. Chronically deacid urolithiasis was increased in geriatnc patients bilitated, bedridden patients may be predisposed to increased with the younger cohort (11versus 5%). Population urinary stone formation secondary to severe immobility and studies have demonstrated serum urate concentrations to subsequent hypercalciuria but this is a different type of pawith age and gender.10 The incidence of gout occurs tient population compared to our outpatient data base. Increased urinary crystals may predispose patients to have between 0.2 and 0.35/1,000 patients, which increases with Approximately 10 to 20% of patients with gouty urinary stones. The incidence of geriatric patients with crys-

B

%

2224

GERIATRIC UROLITHIASIS

talluria (35%) without a history of urinary stones was increased compared to younger adults (6%).21 Moesch et a1

reported increased concentrations of calcium oxalate crystals in geriatric patients compared to a younger group.22 They suggested that oxalate metabolism was altered with advanced age and may promote urinary stone formation. However, no significant increase in urinary oxalate excretion was seen in our geriatric population. Our elderly patients had lower urinary oxalate excretion compared to the younger stone group. Although elderly patients may have increased crystalluria, it is unlikely that urinary stones develop in geriatric patients from increased calcium oxalate crystals (secondary to hyperoxaluria). Geriatric stone formers experienced the first symptomatic stone episode at a later age compared to the younger stone population. Of the geriatric stone patients 60% experienced the first symptomatic urinary stone episode after age 50 years compared to 90% of nongeriatric patients who reported the first stone episode before age 50 years. Geriatric stone patients had similar incidences, recurrence rates, numbers of stone episodes and severity of disease compared to the younger group. CONCLUSIONS

Of patients referred with urinary stone disease 12% were older than 65 years. The incidence and severity of recurrent stone disease were similar between geriatric and younger stone forming patients. Geriatric stone forming patients have an increased incidence of isolated hypocitraturia, uric acid calculi and previous parathyroid surgery. Elderly patients do not have an increased incidence of struvite calculi. Complete metabolic evaluations are critical for complete urinary stone prophylaxis programs irrespective of age. The geriatric stone population is not merely an extension of younger stone forming patients presenting at an older age. Rather, geriatric patients commonly experience the first symptomatic stone episode later in life. REFERENCES

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6. Mhiri,M. N., Achiche, S., Maazoun, F., Bahloul, A. and Njeh, M.: Lithiase urinaire en milieu geriatrique. Ann. d'Urol., 2 6 382,

1995. 7. Ryall, R. L.,Harnett, R. M., Hibberd, C. M., Mazzachi, B. C., Mazzachi, R. D. and Marshall, V. R.: Urinary risk factors in calcium oxalate stone disease: comparison of men and women. Brit. J . Urol., 60:480, 1987. 8. Davies, D. F. and Shock, N. W.: Age changes in glomerular filtration rate, effective renal plasma flow, and tubular excretory capacity in adult males. J . Clin. Invest., 29 296, 1950. 9. Frassetto, L. A.,Morris, R. C., Jr. and Sebastian, A.: Effect of age on blood acid-base composition in adult humans: role of age-related renal functional decline. h e r . J. Physiol., part 2, 271: F1114,1996. 10. Kelly, W. N. and Wortmann, R. L.: Gout and hyperuricemia. In: Textbook of Rheumatology. Edited by W. N. Kelley, S. Ruddy, E. D. H a m s , Jr. and C. B. Sledge. Philadelphia: W. B. Saunders Co., vol. 2,chapt. 80,pp. 1313-1351, 1997. 11. Michet, C. J., Jr., Evans, J . M., Fleming, K. C., O'Duffy, J. D., Jurisson, M. L. and Hunder, G. G.: Common rheumatologic diseases in elderly patients. Mayo Clin. Proc., 70: 1205, 1995. J. Urol.. 154: 12. Stoller. M.L.: Gout and stones or stones and gout? 1670,1995. 13. Riese. R. J . and Sakhaee. J.: Uric acid nephrolithiasis: Dathogenesis and treatment. J. Urol., 148: 7657 1992. 14. Fardellone, P., Sebert, J. L., Garabedian, M., Bellony, R., Maamer, M., Agbomson, F. and Brazier, M.: Prevalence and biological consequences of vitamin D deficiency in elderly institutionalized subjects. Rev. Rheum., 62: 576, 1995. 15. Komar, L., Nieves, J., Cosman, F., Rubin, A., Shen, V. and Lindsay, R.: Calcium homeostasis of a n elderly population upon admission to a nursing home. J. Amer. Ger. SOC.,41: 1057,1993. 16. Whitman, E. D. and Norton, J . A.: Endocrine surgical diseases of elderly patients. Surg. Clin. N. Amer., 74: 127, 1994. 17. Carretier, M. and Barbier, J.: Etiology, pathophysiology and natural history of primary hyperparathyroidism. In: Primary Hyperparathyroidism. Edited by J. Barbier and J. F. Henry. Paris: Springer-Verlag, chapt. 3,pp. 29-36, 1992. 18. Klugman, V. A,, Favus, M. J . and Pak, C. Y. C.: Nephrolithiasis in primary hyperparathyroidism. In: The parathyroids. Edited by J. P. Bilezikaian, M. Levine and R. Marcus. New Y o r k Raven Press, Inc., chapt. 30,pp. 505-517, 1994. 19. Ruijs, C. D., Ottow, R. T. and van Vroonhoven, T. J.: Old age is not a contraindication for surgery in patients with primary hyperparathyroidism. Neth. J. Med., 4 5 101, 1994. 20. Nordenstam, G. R., Brandberg, C. A., Oden, A. S., Svanborg Eden, C. M. and Svanborg, A,: Bacteriuria and mortality in a n elderly population. New Engl. J. Med., 3 1 4 1152,1986. 21. Moesch, C., Charmes, J. P., Gaches, F., Bouthier, F. and Leroux-Robert, C.: Crystalluria prevalence in the elderly. Eur. J. Med., 2 512, 1993. 22. Moesch. C., Charmes, J . P., Bouthier, F. and Leroux-Robert. C.: Calcium oxalate crystalluria in elderly patients and treatments with naftidrofuryl oxalate. Age Ageing, 24: 464, 1995.