Bone loss in autoimmune chronic active hepatitis on maintenance corticosteroid therapy

GASTKO~NTEKOLOGY

LIVER

AND

BILIARY

1985;89:1078-83

TRACT

Bone Loss in Autoimmune Chronic Active Hepatitis on Maintenance Corticosteroid Therapy A. J. STELLON, A. DAVIES, J. COMPSTON,

and R. WILLIAMS

Liver Unit and Department of Radiology of the King’s College Hospital and School and Dentistry, and Department of Histopathology of St. Thomas’ Hospital, London,

To determine the frequency of osteoporosis in patients with autoimmune chronic active hepatitis who are maintained on corticosteroids, both cortical and trabecular bone loss were studied in a group of 36 patients. A significant decrease in both the total trabecular bone volume (p = 0.005) and cortical plate thickness (p = 0.01) of iliac crest biopsy specimens was found in the patients with chronic active hepatitis. Bone mineral content of the radial metaphysis, a site composed of both cortical and trabecular bone, was found to be significantly decreased (p = 0.05). However, no statistical reduction in cortical bone mass of the radial diaphysis and second metacarpal was detected. Altogether, 47% of patients had evidence of either excessive trabecular or cortical bone loss, or both, as judged by histologic and radiologic criteria. The presence of cirrhosis at the time of diagnosis or subsequently did not appear to lead to greater loss of bone mass. However, a weak inverse correlation was found between the product of mean dose and duration of corticosteroid therapy and both the trabecular bone volume and the cortical plate thickness of the iliac crest biopsy specimens. Based on these results, patients with autoimmune chronic active hepatitis on low doses of prednisolone therapy may need to be treated with calcium and vitamin D at an early stage of their disease. Received January 9, 1985. Accepted April 12, 1985. Address requests for reprints to: A. J. Stellon. Liver Unit, King’s College Hospital, Denmark Hill, London SE5, United Kingdom. The present address of J. Compston is Department of Pathology, University Hospital of Wales, Heath Park, Cardiff, United Kingdom. The authors thank A. Webb for preparation of the iliac crest biopsy specimens and are indebted to Advisory Services (Clinical and General) and Robapharm Ltd. for their support of this study. They also thank Professor Tighe for allowing them to work in his department. 0 1985 by the American Gastroenterological Association 0016-5085/85/$3.30

of Medicine England

Corticosteroids have been shown both to induce and to maintain remission in patients with autoimmune chronic active hepatitis (CAH), and long-term therapy is usually required for control of the disease (1,Z). Although in other clinical situations such therapy is known to be associated with the development of osteoporosis (3-8), relatively little has been published with respect to the occurrence of this complication in patients with chronic liver disease who are receiving corticosteroid therapy (9). As osteoporosis is also described in association with the presence of cirrhosis (IO-l3), such a complication may be thought to be even more likely to occur when corticosteroids are administered to such patients. In one previous study (14), 23% of patients with CAH were reported to have evidence of excessive bone loss as judged by metacarpal morphometry. This, being an indicator of cortical bone mass alone, may correlate poorly with other parts of the skeleton especially those areas composed of trabecular bone, as the areas of fracture occurrence are primarily composed of trabecular bone (15-17). In the present study we have investigated both cortical and trabecular bone loss in patients with autoimmune CAH in relation to dose and duration of corticosteroid therapy and the presence of cirrhosis, either as detected initially or developing during the follow-up period.

Materials and Methods Patients Thirty-six into

the

opausal,

study. and

patients, Nineteen

aged of the

immunoserologic

20-66

yr,

34 women and

were were

histologic

entered postmenfindings

Abbreviutions used in this paper: BMUW, bone mineral content/width; CAH, chronic active hepatitis; CA/TA. ratio of cortical area to total area: CT, cortical plate thickness; TBV, trabecular bone volume.

OSTEOPOROSIS IN CHRONIC ACTIVE HEPATITIS

November 1985

fulfilled internationally agreed criteria for autoimmune CAH. Biopsy-proven cirrhosis, documented in one or more biopsy specimens over a period of 1-12 yr, was present in 23 of the 36 patients. At the time of the study all patients were in biochemical and histologic remission as defined by a serum aspartate transaminase level of ~40 IUiL and appearance of chronic persistent hepatitis (mild portal tract mononuclear cell infiltrate in the absence of piecemeal necrosis) on liver biopsy. All patients had received prednisolone before the time of study for a minimum period of 1 yr (median 3.6 yr, range 1-12 yr). The maintenance dose of prednisolone at the time of entry to the study ranged between 5 and 12.5 mglday (median 10 mg/day). Thirty-one patients were taking 50-100 mgiday of azathioprine in addition to prednisolone. Six patients were receiving spironolactone for fluid retention, 2 patients were on thyroxine replacement therapy, and 1 patient was receiving glibenclamide for diabetes. No patient had received prior vitamin D or calcium supplementation and no patient had clinical evidence of steatorrhea. On entry into the study each patient completed a simple questionnaire concerning past fractures, the presence or absence of bone pain, and analgesic intake. Radiology A posteroanterior radiograph of the right hand was obtained in each patient and the total bone width and medullary width at the midpoint of the second, metacarpal shaft were measured using needle-tipped Vernier calipers. The cortical area ratio was calculated from the following formula: CA

rMW12

where CA denotes cortical area, TA total area, TW the total bone width, and MW the medullary width. The CAITA ratio is a measure of the fraction of the shaft volume occupied by compact bone. Normal control values were obtained from 36 subjects not known to suffer from metabolic bone disease. Reproducibility was 1.1%. Separate lateral radiographs of the thoracic and lumbar spine were exposed in each patient and were assessed for the presence of vertebral body collapse. Vertebrae were deemed to show wedging if the wedge angle measured >13”. All radiographs were evaluated by a single observer (A. C. D.) over a period of 2 wk. Photon

Absorptiometry

Bone mineral content of the radius in both arms was determined by a single-photon absorption using the Gambro bone mineral detector with a “‘Am radiation source. The two sites of measurement were a metaphyseal site, 3 cm from the distal radial styloid process (10%-18°b trabecular bone), and a diaphyseal site, 8 cm from the same point (95% cortical bone) (18). A water-filled rubber cuff, with absorptive properties similar to soft tissue, was applied to the arm around the site to be measured and was then carefully positioned over the radiation source. The soft tissue baseline count was determined at a point

1079

between the radius and ulna that gave the maximum counts, so as to eliminate corrections for the degree of fat present in each individual. Bone mineral content (BMC) and width (W) were measured at each site and bone mass was computed. The results are a mean of four scans performed at each site on the radius and are expressed in grams per square centimeter [i.e., BMC/W), a more sensitive index for comparing groups of subjects with various bone dimensions. Normal control values were obtained from 45 healthy subjects, 35 women and 10 men, aged 20-70 yr who were not known to be suffering from metabolic bone disease. The reproducibility at the metaphyseal site was 4% and at the diaphyseal site it was 2.7%. Bone

Histomorphometry

Full thickness transiliac crest biopsies were performed on all patients using an 8-mm modified Bordier trephine under local anesthesia. Wherever possible, two contiguous specimens were obtained 2 cm inferior and posterior to the anterior-superior iliac spine. The specimens were fixed in 10% phosphate-buffered formalin, then dehydrated and defatted, and finally embedded in methyl methacrylate. Nonconsecutive undecalcified 7-km-thick sections were cut with a Jung-K microtome and stained by the von Kossa method using a Van Gieson counterstain. Measurements were obtained using a Zeiss integrating eyepiece (Carl Zeiss Inc., Thornwood, N.Y.) containing 25 points and seven parallel lines at a magnification of X 100 on a minimum of 100 fields on four or more von Kossastained sections. Using an eyepiece micrometer at a magnification of x40, cortical thickness was measured on both the inner and outer plates on a minimum of three von Kossa-stained sections. The following measurements were derived: 1.

2. 3. 4.

5.

Total trabecular bone volume (TBV). This constituted the trabecular bone volume, both mineralized and unmineralized, expressed as a percentage of the total medullary volume, including bone and marrow spaces. Relative osteoid volume. This is the percentage of total TBV occupied by osteoid. Relative osteoid surface. This is the percentage of total trabecular bone surface covered by osteoid. Osteoid index. This is the mean osteoid seam thickness calculated as the ratio of osteoid volume to osteoid surface multiplied by 100. Cortical plate thickness (CT). This is the mean thickness of both the inner and outer cortical plates. Measurements were performed at 10 equidistant points along each cortical plate perpendicular to its outer surface and the mean of these values was obtained.

Normal values for these static parameters were obtained from 39 healthy subjects, 30 women and 9 men, aged 1% 69 yr, the clinical details of which have been previously reported (19). All histomorphometry was performed by one observer (A. S.) to eliminate interobserver variation. All patients gave written informed consent to participate in the trial and the study was approved by King’s College Hospital Ethical Committee on March 30, 1981.

1080

STELLON ET AL.

Statistical

CASTKOENTEROLOCY Vol. 89. No 5

Analysis

p=o.o1 .

The values for each measurement are expressed as fractions of the standard deviation of the mean of the normal value for the patient’s age and sex (Z score). This calculation adjusts each patient’s values for age and sex. A two-tailed, one-sample, t-test procedure was then performed on these values. All other statistical analysis performed used a two-tailed unpaired Student’s t-test for the difference between mean values.

p=N.S.

.

+4?. . p= 0.05 .

+3 -

. . +2 -

Results p=o.o005

The systematic questioning for clinical symptoms of osteoporosis revealed that 3 patients suffered 1 patient suffered generalized aches lower backache, in her limbs, and 2 patients had sustained fractures (wrist 1, humerus 1) before the introduction of corticosteroid therapy. Radiologically, 3 patients had a significantly reduced (>z SD of mean for age- and sex-matched controls) CA/TA ratio of the second metacarpal. However, when the Z scores were grouped together no significant decrease in cortical mass was observed in these patients (Figure 1, Table 1). Examination of the lateral radiographs of the thoracolumbar spine revealed demineralization in i’ patients, although in only 1 patient was a wedged vertebra noted. The bone mineral content of the radius was significantly reduced at the metaphyseal site but not at the diaphyseal site, with 14% of the patients having significant (>z SD) bone mineral loss at both of these sites. In all patients values of osteoid volume, surface, and index were within the normal range, thus excluding the presence of osteomalacia (Table 2). Both the mean total TBV and the mean CT were significantly reduced (Figure 1, Table 1). The percentage of patients with significant loss of TBV and CT (>Z SD) were 17% and 36%, respectively. When the patients with and without cirrhosis at the time of entry into the study were compared, the two groups were well-matched for age, sex, and mean daily dose of prednisolone. Duration of disease and the dose-duration of corticosteroid therapy (mean dose x duration of treatment) were slightly increased in the cirrhotic group, but this increase was not statistically significant (Table 3). The cirrhotic patients had slightly increased bone loss at all sites measured compared with the noncirrhotic group, but this did not reach statistical significance and could be explained by the higher dose-duration of prednisolone therapy (Table 3). Also, only a weak inverse correlation was found between the dose-duration (milligram-years) of corp = ticosteroid therapy and both the TBV (r = -0.39, 0.05) and

CT (r = -0.36,

p = 0.05).

Such

correlations

i

+1

t

t* .. i* - ._a._ :. . .. i t.

.

p =N.S. .

..

.

1’ ... . . . . __?__ : ; 8

.:. .

. .. .

??

.... . ... ..

a

.

. :.

i.

i:

--:-..

:t .* . ..

.

.

2:

D

: . .

.. . :

. 1’ . :

: ..:. .*.I

r . . .

. . .

.

.

. TBV

Figure

CT

MC/W (3cm)

MC/W (km)

CAITA

1. The Z scores for total trabecular bone volume (TBV) and cortical plate thickness (CT] of the iliac crest, radial z bone mineral content of the metaphysis [BMUW,,,] and diaphysis [BMCIW,,,]. and second metacarpal cortical area/total area ratio in the patients with chronic active hepatitis. Dotted line indicates the mean Z score in the patients with chronic active hepatitis.

were not found when other bone mass measurements were compared. In comparing bone loss at various sites measured, significant correlations were found only between the CA/TA and the BMUW ratios at the metaphyseal (r = 0.56, p = 0.01) and the diaphyseal (r = 0.55, p = 0.01)

sites.

On division of the CAH patients into pre- and postmenopausal groups no significant difference in the amount of bone lost at any of the sites could be observed.

Discussion At present there is no standard definition for the presence of osteoporosis apart from the clinical

November

OSTEOPOROSIS

1985

IN CHRONIC

ACTIVE

Table 1. Total Trabecular Bone Volume, Cortical Plate Thickness,” Radial Bone Mineral Content,b Metacarpal Cortical Area to Total Area Ratio in Patients With Chronic Active Hepatitis Subjects Female Controls Patients Controls Patients Controls Patients Male Controls Patients (1) (21

(15) (15) (10) (14) (5) (5)

(9)

Age

Total

(yrl

TBV (%I

20-49

50-59 60-69

30-59

25.3 2 19.9 + 24.1 2 18.2 t 17.0 2 19.0 +

4.9 4.1 5.7 5.4 4.9 4.4

1.47 k 1.20 2 1.28 2 0.97 2 0.82 t 1.04 2

(g/cm’)

0.18 0.25 0.21 0.30 0.16 0.30

0.55 0.53 0.58 0.52 0.52 0.54

t 2 + + 2 2

and Second

BMC/W,eI (g/cm’)

BMCM,,, CT (mm)

0.73 0.73 0.72 0.67 0.65 0.64

0.04 0.07 0.05 0.06 0.06 0.06

19.1 + 3.5

0.82 2 0.16

0.62 2 0.08

14.1 18.3

1.19 0.80

0.54

+ + + k + +

CAiTA

0.04 0.09 0.07 0.06 0.08 0.10

0.856 0.827 0.826 0.789 0.728 0.738

0.81 ? 0.08

2 0.065 ? 0.068 + 0.062 2 0.065 lr 0.071 + 0.064

0.800 + 0.07 0.732 0.843

0.66 0.77

0.49

1081

HEPATITIS

TBV, trabecular bone volume; CT, cortical plate thickness; BMCIW, bone mineral content/width; CAITA, cortical area to total area ratio. The total area ratio (CA/TA), TBV, CT, and BMCiW in patients with chronic active hepatitis are compared with age- and sex-matched controls. Results are expressed as mean + SEM. u CT of the iliac crest. b BMC of the metaphysis (BMCAN,,,) and diaphysis (BMCIW,,,).

syndrome where patients are described as being osteoporotic if collapsed or wedged vertebrae are detected radiologically. In this study we have defined cortical or trabecular osteoporosis as being present if the bone measurement obtained was below the lower unit of normal (>2 SD of mean of age- and sex-matched controls) or if a wedged or collapsed vertebra was present. Using this definition, 47% of patients had evidence of either excessive trabecular or cortical bone loss, or both, as judged by histologic and radiologic criteria. This study has also demonstrated significant trabecular bone loss of both the iliac crest and distal radius, both of which are known also to contain a proportion of cortical bone, in patients with autoimmune CAH who are being maintained in remission by corticosteroid therapy. The greater susceptibility of trabecular bone, rather than cortical bone, to the osteoporosis induced by corticosteroid administration may be related to the higher rate of bone turnover (20). Although cortical bone was not affected to a major extent in this study, this is in contrast to the findings of Epstein et al. (14) which showed that 23% of CAH patients maintained on corticosteroids had evidence of excessive cortical bone loss of the second metacarpal compared with 8% of our patients, despite the use of comparable doses of prednisolone. In that study, however, the patient findings were compared with a normal range published by Garn et al. (21) and not, as in our study, with determinations carried out by the same observer in age- and sex-matched controls. Similar results with respect to the greater degree of trabecular rather than cortical bone loss have been reported to occur in other clinical conditions, such as asthma (7), rheumatoid arthritis (3), and vasculitis (S), treated with long-term corticosteroid therapy.

This study also suggests indirectly that the presence of cirrhosis does not have an additional effect on the development of osteoporosis, although a direct comparison of patients with cirrhosis who have been treated with or without corticosteroids has not been performed. Anecdotal reports in other types of chronic liver disease (22), however, have suggested that accelerated bone loss develops with the introduction of corticosteroid therapy. When bone loss in our patients was correlated with the dose-duration of prednisolone therapy, only a weak, but significant, inverse relationship was obtained between TBV and CT and the doseduration of corticosteroid therapy. This finding is in that contrast to Crilly et al. (23), who found

Table 2. Osteoid Volume, Surface, and Index in Patients With Chronic Active Hepatitis Compared With Age- and Sex-Matched Controls Age Subiects Female Controls Patients Controls Patients Controls Patients

ov

lvrl

(%1

(15) 20-49 (15) (10) 50-59 (14) (5) 80-69 (5)

1.03 " 1.14 2 1.34 2 1.19 k 1.45 k 1.25 2

(9)

1.89 5 0.44

14.9 2 1.6

0.3 1.6

7.0 16.0

OV, osteoid volume; OS, osteoid

01,

Male Controls Patients

30-59

(11 121

Results

are expressed

as mean

0.25 0.34 0.27 0.35 0.31 0.18

01

OS r%l

9.1 * 1.2 9.2 2 1.5 10.3 2 2.5 12.2 * 1.7 9.1 2 1.4 14.4 f 2.2 13.8 ?I 3.0 9.6 + 1.4 8.5 t 1.4 17.6 + 2.9 13.4 + 1.19 9.4 t 1.0

surface; ? SEM.

12.2 + 2.0 4.3 10.0

osteoid

index.

1082

Table

STELLON ET AL.

3. Comparison and Without

GASTROENTEROLOGY Vol. 89. No. 5

of the Clinical Cirrhosis

Details

and Bone Measurements

Cirrhosis (23) Clinical details Age (yr) Men/women Pre-/postmenopausal Prednisolone dose (mgiday) Duration of disease (yr) Dose-duration of corticosteroid therapy (mg-yr) Bone measurements (Z scores) Total trabecular bone volume Cortical plate thickness Radial bone mineral content metaphysis (BMUW,,,) Radial bone mineral content diaphysis (BMUW,,,) Cortical area/total area ratio NS, not significant.

Results are expressed

43.9 5 3.1 1122 10112

in Patients

With Chronic

No cirrhosis (131 40.0

t 4.4

Active

Hepatitis

With

Unpaired NS

1112

616

8.9 ? 0.4

9.4 -t 0.4

NS

4.7 + 0.7 44.3 2 6.7

3.2 ? 0.6 30.9 * 5.5

NS NS

0.20

-0.75

+ 0.30

NS

2 0.30

-1.24

L 0.44

-0.44

c 0.34

NS NS

-1.1 * -1.3

-0.6 5 0.30

t-test

-0.65

+ 0.41

0.17

2 0.28

NS

-0.23

2 0.23

0.13

2 0.17

NS

as mean ‘- SEM

metacarpal bone loss using the CA/TA ratio was significantly inversely correlated with the doseduration of therapy and that this correlation was more significant for patients taking corticosteroids for more than 5 yr. Conflicting reports have been published on whether the bone loss seen in patients on corticosteroids is related to menopausal status (24,25). Our studies suggest that bone loss at whatever site measured appeared to occur to the same extent in both pre- and postmenopausal women. Presumably the reason for the apparent belief that corticosteroids induce osteoporosis more severely in postmenopausal women is that a reduction in bone mass beyond that already present as a result of the postmenopausal state (26) could lead to fracture occurrence. This study has again confirmed that measurements of the appendicular skeleton correlate poorly with those of the axial skeleton, inasmuch as no significant correlation existed between TBV and either the CA/TA ratio or BMUW at both radial sites. A significant positive correlation did exist between sites composed of cortical bone, i.e., metacarpal and diaphyseal site of the radius, and the reason for the positive correlation between CA/TA and the metaphyseal site of the radius presumably is related to the large cortical component present in the latter. The TBV of the iliac crest, although it may not reflect trabecular bone in other parts of the body, does appear to be correlated with the amount of trabecular bone present in the spine (27,28). Computed axial tomography, dual photon absorptiometry, and neutron activation analysis can directly

measure vertebral bone mineral content. However, because these methods were not available to us, our only way of looking at trabecular bone composition was by the total TBV of the iliac crest, the metaphyseal site of the radius, and by direct radiology of the thoracolumbar spine. Because of the correlation of TBV in the iliac crest with the spine, Meunier et al. (29) defined a “TBV fracture threshold” of 11% k 3% at which vertebral collapse appears, independent of sex or age of the patient. Although 6 of our CAH patients were within this range, none had yet developed a crushed vertebra. They remain, however, at high risk because, although low bone mass is one determinant of fracture, trauma is thought to be an additional factor (30). The CT was shown to be significantly reduced in our patients and this may be of clinical relevance with respect to the occurrence of femoral neck fractures. Meunier et al. (31) has recently found that the CT of the iliac crest was the one parameter that was significantly reduced in patients who developed femoral neck fractures. In conclusion, the results of the present study suggest that asymptomatic CAH patients, despite the low doses of prednisolone used in maintenance therapy, have bone loss of a degree that can, as seen in other studies, place them at greater risk of rib, vertebral, radial, and femoral neck fractures. In view of this, treatment measures should be instituted early in the course of CAH so that this risk is minimized. In a recent round-table discussion (32), it was concluded that currently the best approach to the prevention of corticosteroid osteoporosis was an elemental calcium intake of 0.5 g/day combined with

November

OSTEOPOROSIS

1985

vitamin D, 50,000 U twice weekly, or a vitamin D metabolite, 25-hydroxyvitamin D3, 40-60 pgiday, to overcome the calcium malabsorption (4,6,33) seen in these patients treated with corticosteroids.

18.

19.

References 1. Summerskill

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