Variability in risk of gastrointestinal complications with different nonsteroidal anti-inflammatory drugs

Exposure to nonsteroidal anti-inflammatory drugs (NSAIDs) is known to increase substantially the risk of upper gastrointestinal bleeding and/or perforation. A meta-analysis of the available epidemiologic studies has shown that there are wide differences between individual drugs in the risk of inducing gastrointestinal complications. Of the NSAIDs in common use, ibuprofen and diclofenac were found to be associated with the lowest relative risk; indomethacin, naproxen, sulindac, and aspirin were associated with intermediate risk; and azapropazone, tolmetin, ketoprofen, and piroxicam were associated with higher risk. Some of these apparent differences in toxicity may, however, be dose related. The low risk of gastrointestinal complications associated with ibuprofen appears to be attributable to the low doses that are prescribed routinely in clinical practice. Higher doses of ibuprofen were associated with relative risks similar to those of naproxen and indomethacin. Thus, as first-line treatment, patients should be prescribed the lowest effective dose of an NSAID that appears to be associated with a comparatively low risk. This should substantially reduce the morbidity and mortality from serious gastrointestinal complications that are associated with the use of these drugs.

Recent epidemiological studies of the association between hormone replacement therapy and venous thromboembolism. A review

The association between use of hormone replacement therapy (HRT) and the risk of venous thromboembolism (VTE) has been assessed in relatively few epidemiological studies. Evidence from the earliest studies did not support an increased risk of VTE among HRT users. However, methodological limitations in most studies, including small sample size and inadequate control of confounding, did not allow firm conclusions to be made. Most of these limitations have been overcome in 5 recent studies which consistently show that the risk of VTE among women currently using HRT is 2 to 3 times higher than among women not using HRT. The overall relative risk of VTE for women currently using HRT obtained from these studies was 2.6 (95% confidence interval 1.6 to 4.2). This association is unlikely to be explained by confounding or other potential biases affecting observational studies. The risk appears to be more prominent during the first year of HRT use, and in 2 studies the risk disappeared after the first year of therapy. A dose-response relationship, with a doubling of risk among users of high doses of estrogens, was shown in 2 of these studies. No major differences were observed with the different types of therapy, but users of unopposed estrogen therapy and transdermal therapy might be at lower risk than users of opposed regimens and oral preparations. Evidence from these new studies indicates that, among healthy post-menopausal women, between 1 and 2 additional cases of VTE per 10,000 women can be annually attributed to current use of HRT. The Committee on Safety of Medicines in the UK evaluated this risk as small and considered that it does not change the overall benefit-risk profile of HRT for most women.

Risk of hospitalization for upper gastrointestinal tract bleeding associated with ketorolac, other nonsteroidal anti-inflammatory drugs, calcium antagonists, and other antihypertensive drugs

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) cause substantial morbidity and mortality from upper gastrointestinal tract disease. Ketorolac tromethamine has been singled out as an NSAID with a distinct gastrotoxicity profile. Calcium channel blockers, a class of antihypertensive drugs, have also been found to increase the risk of gastrointestinal tract bleeding.

METHODS

We identified 1505 patients hospitalized because of upper gastrointestinal tract bleeding and/or perforation, and we randomly sampled 20,000 controls in the source population.

RESULTS

The adjusted relative risk (RR) for upper gastrointestinal tract bleeding and/or perforation in NSAID users compared with nonusers was 4.4 (95% confidence interval [CI], 3.7-5.3). The risk increased with higher daily doses. Ketorolac presented the highest risk (RR, 24.7; 95% CI, 9.6-63.5) and piroxicam ranked second (RR, 9.5; 95% CI, 6.5-13.8). Ketorolac was 5 times more gastrotoxic than all other NSAIDs (RR, 5.5; 95% CI, 2.1-14.4). The excess risk with ketorolac was observed with both oral and intramuscular administration and was already present during the first week of therapy. Among the various antihypertensive drug classes, beta-blockers were associated with the lowest relative risk (RR, 1.0; 95% CI, 0.7-1.4), and current use of calcium channel blockers with the highest (RR, 1.7; 95% CI, 1.3-2.1). The association with calcium channel blockers declined when adjusting for various markers of comorbidity (RR, 1.4; 95% CI, 1.1-1.8). Past use of calcium channel blockers was also associated with an increased risk (RR, 1.5; 95% CI, 1.3-1.8).

CONCLUSIONS

The excess risk of major upper gastrointestinal tract complications associated with outpatient use of ketorolac suggests an unfavorable risk-benefit assessment compared with other NSAIDs. More data are required to reduce the uncertainty about the apparent small increased risk of upper gastrointestinal tract bleeding in patients using calcium channel blockers.

Renal disease and acid-suppressing drugs

No comparative epidemiological data can be found in the literature on the renal safety of acid-suppressing drugs. We followed-up a cohort of close to 180,000 persons during periods of treatment and non-treatment with five anti-ulcer drugs to evaluate the risk of idiopathic acute renal failure and/or nephrotic syndrome. After reviewing medical records, five patients were found to be cases. Two presented with acute renal failure and three had nephrotic syndrome. Three cases occurred during periods of non-exposure to anti-ulcer drugs. Two cases occurred during current use of ranitidine: one of acute renal failure and one of nephrotic syndrome. No case was encountered during treatment with cimetidine, famotidine, nizatidine or omeprazole. The incidence of idiopathic renal disease in the general population was 1 per 100,000 person-years. The relative risk associated with use of acid-suppressing drugs was 1.8 (95% CI, 0.3-10.7) compared to non-use. These results do not suggest a major increased risk for acute renal injury and/or nephrotic syndrome associated with use of anti-ulcer drugs.

A review of epidemiologic research on drug-induced acute liver injury using the general practice research data base in the United Kingdom

Drug hepatotoxicities have been evaluated in case histories, surveys based on retrospective record reviews, and spontaneous adverse drug reactions reported to national pharmacovigilance systems, but in relatively few epidemiologic studies. To identify and quantify the risk of acute liver injury associated with individual drugs, we reviewed and integrated all the published epidemiologic research on the subject. The source population for the eight studies was general population registered on a single large general practice-based computerized data base. All were retrospective cohort studies, but some had a case-control design nested within the source cohort. Participants were selected according to their use of selected agents (nonsteroidal antiinflammatory drugs [NSAIDs], antibiotics, acid-suppressing drugs, other drugs suspected of being hepatotoxic) during the study period. Among the agents, we found a group of important hepatotoxic drugs with an associated incidence rate of acute liver injury greater than 100/100,000 users, including chlorpromazine and isoniazid. Agents with less risk but greater than 10/100,000 users were amoxicillin-clavulanic acid and cimetidine. A third group of drugs had an associated incidence rate of acute liver injury of less than 10/100,000 users. Our results provide evidence of relative safety for commonly administered agents such as NSAIDs, amoxicillin, omeprazole, and ranitidine. We also quantified important suspected liver toxicity, providing a reasonable precise risk estimate of clinical liver injury associated with chlorpromazine, isoniazid, and amoxicillin-clavulanic acid.

Nonsteroidal antiinflammatory drugs, ulcers and risk: a collaborative meta-analysis

Nonsteroidal antiinflammatory drugs (NSAIDs) are associated with a high prevalence of gastrointestinal toxicity. Comparisons of the risks associated with individual NSAIDs are needed, but most clinical studies in this area are not ideally suited for use in meta-analyses. These difficulties can be overcome by using strict criteria for the inclusion of studies, and by reanalyzing previous data, updated by authors where possible. In doing so, this meta-analysis compared the relative risk of serious toxicity associated with 14 NSAIDs from 12 studies with the risks of ibuprofen. These results were supported by a novel "summary ranking" analysis, which was weighted to limit the influence of smaller studies. Wide variations in relative risk among NSAIDs were observed with piroxicam and azapropazone being the most toxic. Ibuprofen was associated with the least risk, probably because of its widespread use as a low-dose analgesic. Five studies provided comparative data on NSAIDs at "high" and "low" doses (as defined in the original reports), showing that the risk of toxicity was dose related. Furthermore, at full antiinflammatory doses, the risk associated with ibuprofen was similar to that of naproxen and diclofenac. These analyses show that NSAIDs vary more in toxicity than in efficacy. First-line therapy should be started with the lowest effective dose of a less toxic NSAID, moving to higher doses or a more toxic NSAID only if the clinical situation demands it. Newer NSAIDs, such as selective cyclooxygenase-2 inhibitors, may provide safer antiinflammatory therapy.

Hormone replacement therapy and risk of venous thromboembolism: population based case-control study

OBJECTIVE

To evaluate the association between use of hormone replacement therapy and the risk of idiopathic venous thromboembolism.

DESIGN

Population based case-control study.

SETTING

Population enrolled in the General Practice Research Database, United Kingdom.

SUBJECTS

A cohort of 347,253 women aged 50 to 79 without major risk factors for venous thromboembolism was identified. Cases were 292 women admitted to hospital for a first episode of pulmonary embolism or deep venous thrombosis; 10,000 controls were randomly selected from the source cohort.

MAIN OUTCOME MEASURES

Adjusted relative risks estimated from unconditional logistic regression.

RESULTS

The adjusted odds ratio of venous thromboembolism for current use of hormone replacement therapy compared with non-users was 2.1 (95% confidence interval 1.4 to 3.2). This increased risk was restricted to first year users, with odds ratios of 4.6 (2.5 to 8.4) during the first six months and 3.0 (1.4 to 6.5) 6-12 months after starting treatment. No major risk differences were observed between users of low and high doses of oestrogens, unopposed and opposed treatment, and oral and transdermal preparations. The risk of idiopathic venous thromboembolism among non-users of replacement therapy was estimated to be 1.3 per 10,000 women per year. Among current users, idiopathic venous thromboembolism occurs at two to three times the rate in non-users, resulting in one to two additional cases per 10,000 women per year.

CONCLUSIONS

Current use of hormone replacement therapy was associated with a higher risk of venous thromboembolism, although the risk seemed to be restricted to the first year of use.

The risk of acute liver injury associated with cimetidine and other acid-suppressing anti-ulcer drugs

AIMS

The objective of this study was to estimate the risk of acute liver injury associated with individual acid-suppressing drugs and assess the role of dose and duration of treatment.

METHODS

We used a nested case-control study design within a cohort of over 100,000 users of cimetidine, famotidine, omeprazole and ranitidine. The primary source of information was the General Practitioners Research Database. We identified 108,981 persons aged 20-74 years who received at least one prescription for cimetidine, famotidine, omeprazole, or ranitidine during 1990-93, and we ascertained the first occurrence of clinically acute liver injury referred to a specialist or admitted to a hospital.

RESULTS

After review of medical records, 33 patients were considered eligible cases of idiopathic acute liver injury with no fatal cases. The type of liver injury was hepatocellular in almost half of the cases, and 80% of all cases presented with jaundice. Twelve cases occurred among current users of cimetidine, five among ranitidine users and one in an omeprazole user. The absolute risk of acute liver injury associated with cimetidine was estimated to be slightly greater than one per 5000 users of cimetidine. The adjusted relative risk (RRs) and 95% CI of developing acute liver injury associated with current use of cimetidine compared to non-use was 5.5 (1.9-15.9), with omeprazole 2.1 (0.2-19.2) and with ranitidine 1.7 (0.5-5.8). In the absence of concomitant use of other hepatotoxic drugs, the RR with cimetidine was 14.4 (2.9-73.7). Among users of cimetidine, the risk was especially high in the first 2 months of starting therapy (RR: 11.3, 3.7-35.1) and at daily doses of 800 mg or greater (RR: 8.8, 3.0-26.0).

CONCLUSIONS

Cimetidine was the individual anti-ulcer drug with the highest risk of developing symptomatic acute liver disease. Further data are required to confirm this finding. Our study indicates that there is a dose relationship and a short latent period between cimetidine treatment and acute liver injury.

Individual nonsteroidal antiinflammatory drugs and other risk factors for upper gastrointestinal bleeding and perforation

We conducted a nested case-control study of 1,377 cases of upper gastrointestinal bleeding or perforation (UGIB) and 10,000 controls to evaluate the association of individual nonsteroidal antiinflammatory drugs (NSAIDs), utilization characteristics, and other risk factors for these conditions. Age was the strongest risk factor for UGIB. Male gender, history of complicated peptide ulcer disease, and current use of steroids were also risk factors for UGIB. The adjusted odds ratio (OR) for current NSAID use was 4.3 [95% confidence interval (CI) = 3.7-5.0]. The ORs for current NSAID use were similar for fatal cases and for the gastric, duodenal, prepyloric, and multiple sites of lesion, but the OR was substantially increased for perforations (OR = 16.9;95% CI = 9.1-31.5). Women age 80 years and older experienced the greater effect of NSAID use. Current users of multiple NSAIDs and recent switchers showed ORs of 9.0 and 6.2, respectively. Ibuprofen showed the lowest OR and diflunisal, the highest. ORs for low, medium, and high NSAID daily dose were 2.9, 4.2, and 5.8, respectively. This trend was present among new, short-term, and long-term users. Simultaneous use of multiple NSAIDs as well as use of a single individual NSAID at high doses greatly increases the risk of complicated peptic ulcer disease.

Nonsteroidal anti-inflammatory drugs and the risk of hospitalization for acute renal failure

BACKGROUND

Few studies have evaluated the association between use of nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of idiopathic acute renal failure (ARF) in the general population.

METHODS

Population-based case-control study among persons in the Canadian province of Saskatchewan who received at least 1 NSAID prescription between January 1, 1982, and December 31, 1986. Health department databases were used for case detection, as the sampling frame for selecting controls (n = 1997), and as the primary source of information on drug use and comorbidity. A total of 306 hospital records were reviewed. Twenty-eight patients who were hospitalized fulfilled the diagnostic criteria for ARF.

RESULTS

The incidence rate of hospitalization for ARF among the general population not exposed to NSAIDs was 2 per 100000 person-years. Current exposure to NSAIDs, acetylsalicylic acid and other nephrotoxic drugs, male gender, increasing age, cardiovascular comorbidity, and recent hospitalization for disorders other than renal were found to be independent risk factors for ARF. Current NSAID users had an adjusted odds ratio for ARF of 4.1 (95% confidence interval, 1.5-10.8). The risk of ARF was especially high during the first month of use (odds ratio, 8.5). For prescribed dose, we found that users of high daily doses of NSAIDs experienced an odds ratio of 9.8 for ARF.

CONCLUSIONS

In the general population, hospitalizations for ARF were found to be a rare condition. The 4-fold increase in risk associated with NSAID use was dose-dependent and occurred especially during the first month of therapy. Concurrent comedication with other potentially nephrotoxic agents should be prescribed with care, especially in the elderly.

Nonsteroidal anti-inflammatory drugs and the risk of hospitalization for acute renal failure

BACKGROUND

Few studies have evaluated the association between use of nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of idiopathic acute renal failure (ARF) in the general population.

METHODS

Population-based case-control study among persons in the Canadian province of Saskatchewan who received at least 1 NSAID prescription between January 1, 1982, and December 31, 1986. Health department databases were used for case detection, as the sampling frame for selecting controls (n = 1997), and as the primary source of information on drug use and comorbidity. A total of 306 hospital records were reviewed. Twenty-eight patients who were hospitalized fulfilled the diagnostic criteria for ARF.

RESULTS

The incidence rate of hospitalization for ARF among the general population not exposed to NSAIDs was 2 per 100000 person-years. Current exposure to NSAIDs, acetylsalicylic acid and other nephrotoxic drugs, male gender, increasing age, cardiovascular comorbidity, and recent hospitalization for disorders other than renal were found to be independent risk factors for ARF. Current NSAID users had an adjusted odds ratio for ARF of 4.1 (95% confidence interval, 1.5-10.8). The risk of ARF was especially high during the first month of use (odds ratio, 8.5). For prescribed dose, we found that users of high daily doses of NSAIDs experienced an odds ratio of 9.8 for ARF.

CONCLUSIONS

In the general population, hospitalizations for ARF were found to be a rare condition. The 4-fold increase in risk associated with NSAID use was dose-dependent and occurred especially during the first month of therapy. Concurrent comedication with other potentially nephrotoxic agents should be prescribed with care, especially in the elderly.

A cohort study of the ocular safety of anti-ulcer drugs

1. Recently, some cases have been reported where intravenous use of omeprazole was followed by loss of vision. We followed up a cohort of close to 140,000 persons during periods of treatment and non-treatment with five anti-ulcer drugs. 2. The relative risk of vascular disorders of the eye during use of omeprazole compared with non-use was 1.8 (95% CI 0.5-6.0). Use of other anti-ulcer drugs was associated with a similar risk of vascular disorders. The relative risk associated with current use of any anti-ulcer drug was 1.9 (95% CI 1.1-3.4). We did not find a single case of optic inflammatory disorder during treatment with any of the five anti-ulcer drugs. 3. These results do not suggest a major increased risk for vascular or inflammatory disorders of the eye associated with use of omeprazole or other anti-ulcer drugs.

Risk of acute liver injury associated with the combination of amoxicillin and clavulanic acid

BACKGROUND

Amoxicillin-clavulanic acid combination-associated hepatitis and jaundice was first identified in 1988. Numerous case reports and case series have been published since then, but there is no precise estimate of this risk.

METHODS

A retrospective cohort study in the United Kingdom to estimate the risk of acute liver injury associated with the combination of amoxicillin and clavulanic acid and compare it with the one of amoxicillin alone. Data were derived from a cohort of 93,433 users of the combination drug amoxicillin-clavulanic acid and 360,333 users of amoxicillin alone who were aged between 10 and 79 years and who were followed up from 1991 through 1992. After reviewing the information on subjects with suspected liver injury that was recorded on computer files, the clinical records of 177 patients from the attending general practitioners were requested.

RESULTS

They were 35 cases of idiopathic acute liver injury. None was fatal. There were 14 cases of acute liver injury among users of amoxicillin alone. The type of liver injury was hepatocellular in half the cases. There were 21 cases of acute liver injury among users of amoxicillin and clavulanic acid together. The type of liver injury was cholestatic in three quarters of the cases. The incidence rates and 95% confidence intervals (CIs) of developing acute liver injury associated with the combination of amoxicillin and clavulanic acid and amoxicillin alone were 1.7 (1.1-2.7) and 0.3 (.02-0.5) per 10 000 prescriptions, respectively. The rate ratios and 95% CIs of acute liver injury for amoxicillin and clavulanic acid together compared with amoxicillin alone were 6.3 (3.2-12.7) for all patients and 8.4 (3.6-20.8) for patients presenting with jaundice. Among users of amoxicillin and clavulanic acid together, the risk of developing acute liver injury was more than 3 times greater after a course of 2 or more consecutive prescriptions than after a single course of therapy. The risk also increased with age among users of amoxicillin and clavulanic acid together. The combination of advancing age and repeated prescriptions resulted in a risk of developing acute liver injury greater than 1 per 1000 users of amoxicillin and clavulanic acid together.

Risk of acute liver injury associated with the combination of amoxicillin and clavulanic acid

BACKGROUND

Amoxicillin-clavulanic acid combination-associated hepatitis and jaundice was first identified in 1988. Numerous case reports and case series have been published since then, but there is no precise estimate of this risk.

METHODS

A retrospective cohort study in the United Kingdom to estimate the risk of acute liver injury associated with the combination of amoxicillin and clavulanic acid and compare it with the one of amoxicillin alone. Data were derived from a cohort of 93,433 users of the combination drug amoxicillin-clavulanic acid and 360,333 users of amoxicillin alone who were aged between 10 and 79 years and who were followed up from 1991 through 1992. After reviewing the information on subjects with suspected liver injury that was recorded on computer files, the clinical records of 177 patients from the attending general practitioners were requested.

RESULTS

They were 35 cases of idiopathic acute liver injury. None was fatal. There were 14 cases of acute liver injury among users of amoxicillin alone. The type of liver injury was hepatocellular in half the cases. There were 21 cases of acute liver injury among users of amoxicillin and clavulanic acid together. The type of liver injury was cholestatic in three quarters of the cases. The incidence rates and 95% confidence intervals (CIs) of developing acute liver injury associated with the combination of amoxicillin and clavulanic acid and amoxicillin alone were 1.7 (1.1-2.7) and 0.3 (.02-0.5) per 10 000 prescriptions, respectively. The rate ratios and 95% CIs of acute liver injury for amoxicillin and clavulanic acid together compared with amoxicillin alone were 6.3 (3.2-12.7) for all patients and 8.4 (3.6-20.8) for patients presenting with jaundice. Among users of amoxicillin and clavulanic acid together, the risk of developing acute liver injury was more than 3 times greater after a course of 2 or more consecutive prescriptions than after a single course of therapy. The risk also increased with age among users of amoxicillin and clavulanic acid together. The combination of advancing age and repeated prescriptions resulted in a risk of developing acute liver injury greater than 1 per 1000 users of amoxicillin and clavulanic acid together.

Positive predictive value of ICD-9 codes in the identification of cases of complicated peptic ulcer disease in the Saskatchewan hospital automated database

We examined the positive predictive value of the International Classification of Diseases, 9th revision (ICD-9), codes used to identify cases of complicated peptic ulcer disease from the Saskatchewan Hospital automated database. Nonspecific and site- and lesion-specific codes were used in case detection to increase the sensitivity of the initial computer search. Review of the hospital records of 1,762 potential cases resulted in 1,375 confirmed cases. The positive predictive value of site and lesion-specific codes was about 90% and was about 70% for the nonspecific codes. Almost 50% of cases, however, would have been missed if the nonspecific codes had not been used.

Risk of upper gastrointestinal bleeding and perforation associated with individual non-steroidal anti-inflammatory drugs

Exposure to non-steroidal anti-inflammatory drugs (NSAIDs) is known to increase substantially the risk of upper gastrointestinal bleeding and perforation (UGIB). We have carried out a population-based retrospective case-control study to assess the variation in risk associated with various individual NSAIDs, with adjustment for features of use and other independent risk factors. The study sample comprised 1457 cases of UGIB and 10,000 control subjects identified from general practitioners' computerised records in the UK. The adjusted estimate of relative risk of UGIB associated with current NSAID use was 4.7 (95% CI 3.8-5.7). Previous UGIB was the single most important predictor of UGIB (relative risk 13.5 [10.3-17.7]). For all NSAIDs together, the risk was greater for high doses than for low doses (7.0 [5.2-9.6] vs 2.6 [1.8-3.8]). The estimates of risk associated with the individual NSAIDs varied widely. Users of azapropazone (23.4 [6.9-79.5]) and piroxicam (18.0 [8.2-39.6]) had the highest risk of UGIB among the NSAIDs studied. All the other NSAIDs with sufficient data for individual analysis (ibuprofen, naproxen, diclofenac, ketoprofen, and indomethacin) had relative risks similar to that for overall NSAID use. NSAIDS should be used cautiously in patients who have other risk factors for UGIB; these include advanced age, smoking, history of peptic ulcer, and use of oral corticosteroids or anticoagulants.

Risk of gynaecomastia associated with cimetidine, omeprazole, and other antiulcer drugs

OBJECTIVE

To study the risk of gynaecomastia associated with cimetidine, misoprostol, omeprazole and ranitidine.

DESIGN

Open cohort study with nested case-control analysis.

SETTING

General practices in United Kingdom that had computerised offices, 1989-92.

SUBJECTS

81,535 men aged 25-84 years who received at least one prescription for cimetidine, misoprostol, omeprazole, or ranitidine during the study period.

MAIN OUTCOME MEASURES

New occurrences of idiopathic gynaecomastia diagnosed by general practitioner.

RESULTS

The relative risk of gynaecomastia for current users of cimetidine compared with non-users was 7.2 (95% confidence interval 4.5 to 11.3). Relative risks for misoprostol, omeprazole, and ranitidine were 2.0 (0.1 to 10.7), 0.6 (0.1 to 3.3), and 1.5 (0.8 to 2.6), respectively. Current users of cimetidine on a daily dose > or = 1000 mg had more than 40 times the risk of developing gynaecomastia than non-users. The period of highest risk was seven to 12 months after starting cimetidine treatment. Spironolactone (relative risk 9.3 (3.3 to 26.1)) and verapamil (9.7 (2.6 to 36.0)) were associated with a relative risk of gynaecomastia comparable to one for cimetidine.

CONCLUSIONS

Use of cimetidine, but not the three other antiulcer drugs, is associated with a substantially greater risk of gynaecomastia in men. A strong dose-response relation was present among cimetidine users.

Acute liver injury associated with nonsteroidal anti-inflammatory drugs and the role of risk factors

BACKGROUND

Hospitalizations for acute liver injury in the absence of a viral infection or any other well-defined pathologic finding that could have caused it is rare. In this study, we included both outpatients and hospitalized patients with acute liver injury to estimate the risk of clinically important acute liver injury associated with the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and to study the role of certain risk factors.

METHODS

This was a retrospective cohort study with secondary case-control analysis. The study included 536 general practitioners' practices in England and Wales for the period October 1987 through August 1991. A total of 625,307 persons who received more than 2 million prescriptions for one of 12 NSAIDs were followed up to estimate the risk of newly diagnosed acute liver injury.

RESULTS

There were 23 cases of acute liver injury. The incidence of acute liver injury was 3.7 per 100,000 NSAID users or 1.1 per 100,000 NSAID prescriptions. None of the cases had a fatal outcome. Sulindac was the only NSAID with a substantially greater risk than that for the overall NSAID group. Users of NSAIDs who had rheumatoid arthritis had a 10-fold increased risk of acute liver injury compared with NSAID-treated patients with osteoarthritis. Concomitant exposure to other hepatotoxic medications also increased the risk. Transient minor increases in liver test values were not a useful predictor of diagnosed NSAID-associated acute liver injury.

CONCLUSIONS

Although NSAIDs have been found to be associated with acute liver injury in a small number of persons, the risk is sufficiently small as to be of minimal concern for most NSAIDs.

The increased risk of hospitalizations for acute liver injury in a population with exposure to multiple drugs

We conducted a nested case-control study to estimate and compare the relative risks for hospitalizations for newly diagnosed acute liver injury associated with the use of non-steroidal antiinflammatory drugs (NSAIDs) and other hepatotoxic drugs and their interaction. The source population comprised 228,392 members of the Saskatchewan Health Plan from 1982 to 1986. We used hospital records and the databases of the Department of Health. Thirty-four cases with confirmed liver injury were hospitalized. We randomly selected 500 controls from the source population. Crude risks ranged from 1 case per 100,000 prescriptions in current users of methyldopa, ampicillin, or NSAIDs to 14 cases per 100,000 prescriptions in current users of erythromycin estolate. The age-adjusted odds ratios for current users of NSAIDs was 1.8 [95% confidence interval (CI) = 0.8-3.7] and for other hepatotoxic drugs 5.9 (95% CI = 2.8-12.4). The adjusted relative excess risk due to the interaction between current exposure to both categories of drugs was 3.6, accounting for 31% of the cases of acute liver injury among those with exposure to both types of drugs. We conclude that the risk of hospitalization for acute noninfectious liver injury is different among users of various individual potentially hepatotoxic drugs. Concomitant current exposure to two or more drugs increases this risk above what would merely be expected from the sum of the individual risks.

Nonsteroidal antiinflammatory drugs and certain rare, serious adverse events: a cohort study

We performed a population-based study of over 100,000 users of diclofenac, naproxen, or piroxicam to identify cases of important blood, skin, central nervous system, kidney, pancreas, or pulmonary disorders caused by these drugs. In three cases a causal relation seemed likely; one of hemolytic anemia attributed to diclofenac, one of neutropenia attributed to naproxen, and one of pancreatitis attributed to piroxicam. In 13 additional cases a causal connection seemed unlikely but could not be fully ruled out. We conclude that such illnesses are uncommonly caused by the three agents studied.

The role of non-steroidal anti-inflammatory drugs in acute liver injury

OBJECTIVE

To investigate the association between use of non-steroidal anti-inflammatory drugs and serious, acute non-infectious liver injury.

DESIGN

Retrospective cohort study, cross over design.

SETTING

Health records from provincial database in Saskatchewan, Canada, 1982-6.

SUBJECTS

228,392 adults who contributed 645,456 person years. All were either using or had used non-steroidal anti-inflammatory drugs.

MAIN OUTCOME MEASURES

Number and type of prescriptions for non-steroidal anti-inflammatory drugs. Admission to hospital for newly diagnosed acute liver injury.

RESULTS

There were 34 admissions to hospital; 16 among subjects currently using non-steroidal anti-inflammatory drugs and 18 among subjects who were not. The incidence rate among current users was 9 per 100,000 person years (95% confidence interval 6 to 15 per 100,000 person years). Subjects currently using non-steroidal anti-inflammatory drugs had twice the risk of newly diagnosed liver injury as those not currently taking these drugs (rate ratio 2.3; 95% confidence interval 1.1 to 4.9) and an excess risk of 5 per 100,000 person years. The age and sex adjusted risk ratio was 1.7 (0.8 to 3.7). The strength of the association increased when only cases with no concomitant use of other hepatotoxic drugs were considered (4.0; 0.9 to 19.0). The rate ratio for people having received one to nine prescriptions was constant. There was no increased risk with long duration of treatment (1.0; 0.3 to 3.5).

CONCLUSIONS

There is a small excess risk of serious, acute non-infectious liver injury associated with the use of non-steroidal anti-inflammatory drugs.

The impact of research quality and study design on epidemiologic estimates of the effect of nonsteroidal anti-inflammatory drugs on upper gastrointestinal tract disease

BACKGROUND

Considerable differences in the estimates of the risk of upper gastrointestinal tract disease associated with treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) have been observed. We conducted a meta-analysis of epidemiologic studies of upper gastrointestinal tract disease related to NSAIDs to answer the following research questions: Are study characteristics (study design and quality) associated with different estimates of risk, for both aspirin and nonaspirin NSAIDs? Does the risk increase for particular groups of patients, such as women and the elderly?

METHODS

Thirty-four studies addressing severe upper gastrointestinal tract disease associated with NSAIDs (including aspirin and nonaspirin NSAIDs) were examined and scored according to a quality checklist that we designed for this review.

RESULTS

Only 44% of the studies controlled for major confounding variables (age and sex). While exposure was defined as current in 40% and 78% of the studies for nonaspirin NSAIDs and aspirin, respectively, few investigations checked for history of ulcer disease and concurrent diseases or other comedications known to be risk factors for upper gastrointestinal tract bleeding. The overall risk ratio, by means of a random-effects regression model, was 3.0 (95% confidence interval, 1.9 to 4.7). The individual estimates for aspirin and nonaspirin NSAIDs were similar. Both with and without control for quality, cohort studies provided a lower risk ratio estimate than did case-control studies.

CONCLUSIONS

The design and quality of the studies appear to be strong independent predictors of the risk estimate; cohort studies were associated with lower risk estimates than case-control studies, and satisfactory studies were associated with lower risk estimates than unsatisfactory studies.

Nonsteroidal antiinflammatory drugs and gastrointestinal hospitalizations in Saskatchewan: a cohort study

We evaluated the association between individual nonsteroidal antiinflammatory drugs (NSAIDs) and gastrointestinal (GI) toxicity in a retrospective cohort study aimed at examining and comparing the incidence of serious gastrointestinal disorders among NSAIDs users. We observed 2,302 GI hospitalizations among diclofenac, indomethacin, naproxen, piroxicam, sulindac, and other NSAIDs users in the province of Saskatchewan, Canada, from 1982 to 1986 for 228,392 persons who contributed 679,075 person-years of follow-up and filled close to 1.5 million NSAID prescriptions. Current NSAID users presented an increased risk of GI hospitalization [rate ratio (RR) = 3.9, 95% confidence interval = 3.5-4.4]. RRs decreased as time since the last prescription increased: 2.2 (1.9-2.6) for recent past users and 1.3 (1.1-1.5) for less recent past users. Among current users, RRs were the highest in indomethacin users (5.1, 4.3-6.0), and the lowest in sulindac users (3.1, 2.3-4.2). All of these results are adjusted for calendar time, sex, and age. Age showed a particularly strong association with the risk of GI hospitalization.