Fatal upper gastrointestinal hemorrhage or perforation among users and nonusers of nonsteroidal anti-inflammatory drugs in Saskatchewan, Canada 1983

The use of prescription claims databases in pharmacoepidemiological research: the accuracy and comprehensiveness of the prescription claims database in Québec

Despite the potential benefits of using prescription claims databases for pharmacoepidemiological research, little work has been reported on the nature of available information or its accuracy. The purpose of this study was to describe information contained within the prescription claims database in Québec, and to assess the accuracy of drug information that might be used to monitor drug exposure and physician prescribing. The comprehensiveness of the prescriptions claims database was assessed by examining 1,917,214 records of dispensed prescriptions for a regionally stratified random sample of 65,349 Québec elderly in 1990. We found that values in key fields (individual identifiers, drug, quantity, date dispensed and duration) were missing or out of range in 0-0.4% of records. The accuracy of data were examined in 723 prescriptions filled by 306 elderly patients attending one internal medicine clinic. Of these prescriptions, 83% were filled by the patient and correctly identified the patient and drug and in 89% of these 599 records, the prescribing physician was correctly identified. The quantity and duration of the prescriptions were accurate in 69.1% and 72.1% of records, respectively. We conclude that the prescription claims database in Québec may represent one of the most accurate means of determining drugs dispensed to individuals. There may be limitations in using this database for dosing information.

Impact of preexisting health conditions on the outcome of an adverse drug reaction alerting program: gastrointestinal disorders before piroxicam and sulindac therapy

OBJECTIVE

To assess the impact of data concerning preexisting serious gastrointestinal (GI) disorders before piroxicam and sulindac therapy in an acute adverse drug reaction alerting program.

DESIGN

Cohort study.

SETTING

Saskatchewan province's prescription drug and healthcare insurance system covering a population of approximately 1 million.

PARTICIPANTS

The first 20,000 new patients who were dispensed piroxicam in 1982 and the first 20,000 patients who were dispensed sulindac in 1979-1981 through the Saskatchewan drug plan.

MAIN OUTCOME MEASURES

Physician services and hospitalizations with a diagnosis of peptic ulceration or GI hemorrhage within 30 days of the first piroxicam or sulindac prescription.

RESULTS

Rates of physician services for peptic ulceration or GI hemorrhage in the 30 days after starting piroxicam or sulindac therapy for patients who had services or hospitalizations for serious stomach or duodenum disorders in the 90 days before their prescriptions were significantly greater than the corresponding rates for patients without a recent history of these conditions (piroxicam: odds ratio [OR] = 7.89; 95% confidence interval [CI] = 5.71 to 10.91; p < 0.001; sulindac: OR = 24.08; 95% CI = 18.99 to 30.54; p < 0.001). Also, the rate of hospitalizations for peptic ulceration or GI hemorrhage in the 30 days after starting sulindac therapy for patients who had services for the conditions in the previous 90 days was significantly greater than the rate for patients who did not (OR = 10.91; 95% CI = 5.70 to 20.87; p < 0.001).

CONCLUSIONS

Rates of serious GI disorders in patients taking piroxicam and sulindac with a recent history of such disorders were larger than those in the other patients. However, because the proportion of individuals with recent serious GI disorders is small, these differences are lost in an overall assessment of patients taking these drugs. Data regarding preexisting health conditions are essential in adverse drug reaction alerting program and, indeed, in all evaluations of adverse reactions.

Risk of traffic accident injury after a prescription for a benzodiazepine

The objective of this study was to assess the risk of hospitalization for injuries received in traffic accidents after a first prescription for benzodiazepines (BZD) was filled. Saskatchewan Health supplied study populations of 78,000 adults who received BZD hypnotics, 148,000 who received BZD anxiolytics, and 98,000 control subjects. These populations were monitored for 2 months after the index prescription fill-date for hospitalizations due to traffic accidents. Analysis showed an odds ratio (OR) of 3.9 (1.9 to 8.3) for persons taking BZD hypnotics and an OR of 2.5 (1.2 to 5.2) for those taking BZD anxiolytics, with regards to hospitalization due to traffic accidents within 4 weeks after the prescription was filled. Within 2 weeks after the prescription was filled, the Or had risen to 6.5 (1.9 to 22.4) for hypnotics and 5.6 (1.7 to 18.4) for anxiolytics. After 1 week, the ORs were even higher (9.1 and 13.5), but the confidence limits were wide. The highest risk groups were the youngest age group (20 to 39 years old) and males. From a public health view, the high ORs are of concern and action for prevention is needed.

Nonsteroidal anti-inflammatory drugs and upper gastrointestinal bleeding, identifying high-risk groups by excess risk estimates

BACKGROUND

The relationship between use of nonsteroidal anti-inflammatory drugs (NSAID) and severe upper gastrointestinal bleeding (UGB) has been established beyond reasonable doubt. The literature on risk factors has almost exclusively focused on comparisons of relative risks in subgroups of patients: men versus women, old versus young and so forth. However, from a pragmatic, clinical viewpoint, only the excess risk provides a meaningful, robust measure of the magnitude of risk factors. The purpose of the study was to determine the excess risks in subgroups of patients and to characterize the utilization pattern of NSAIDs.

METHODS

A registry-based cohort study was conducted in a prescription and diagnosis registry in Odense, which covered a population of 207,000 persons for a period of 19 months.

RESULTS

In total, 183 (113 men and 70 women) UGB patients were identified, of whom 37 were current users of NSAIDs. The standardized incidence rate of UGB was 46 per 100,000 person-years for nonexposed and 253 per 100,000 person-years for exposed person-time, yielding an excess risk of 207 per 100,000 person-years (confidence interval (CI), 132-319) and a standardized incidence ratio (SIR) of 5.5 (CI, 3.9-7.9). Men had higher excess risk than women (277 versus 150 per 100,000 person-years). The SIR decreased with increasing duration of exposure. The excess risk was particularly high in persons aged 75 years or more (1258 per 100,000 person-years) and in patients with a history of peptic ulcer (879 per 100,000 person-years), being about 10- and 5-fold higher than in the complementary groups. NSAID utilization was remarkably sporadic. We found 31,503 users and a median purchase of 20 defined daily doses. Short-term use was highly prevalent in all age groups. Women, the elderly, and persons with a history of ulcer had a higher prevalence of NSAID use than others.

CONCLUSIONS

A history of peptic ulcer is associated with adverse outcome of NSAID therapy and should be regarded as a relative contraindication. A similarly strong effect of high age was shown. Male sex and short-term use are minor risk factors. The incidence of NSAID-related UGB can probably be reduced without affecting the overall utilization of NSAIDs.

[Formation of a cohort of opiate addicts through linkage of confidential records]

The need to combine several files in order to create a cohort of opiate addicts, sufficiently large for the analysis of its mortality, requires use of the probabilistic method of record linkage. This study is a preliminary phase in which two sub-files of the Hospital del Mar (Barcelona) Register of toxicological emergencies are linked. This phase served to adapt probabilistic record linkage to our files, develop computer programs, define agreement criteria, and evaluate the validity and performance of the method. In order to safeguard confidentiality, identification variables were limited to sex, birth date and three initial letters from each surname. The automated probabilistic linkage was seen to be feasible, valid and efficient; in contrast to deterministic approaches, sensitivities and specificities above 95% were obtained with visual reviewing of under 5% of the records. Difficulties encountered during the process are discussed.

Disability and severe gastrointestinal hemorrhage. A prospective study of community-dwelling older persons

OBJECTIVE

To describe the occurrence of severe gastrointestinal bleeding in community-dwelling older persons and to examine whether disability is a risk factor for this life-threatening condition independent of other known predictors.

DESIGN

Prospective cohort survey.

SETTING

Three communities of the Established Populations for Epidemiologic Studies of the Elderly (EPESE).

PARTICIPANTS

8205 persons age > or = 68 years.

MEASUREMENTS

The hospital discharge diagnoses provided by the Medicare Provider Analysis and Review files and the death certificates were prospectively surveyed for 3 years. Those with at least 1 discharge diagnosis of gastrointestinal bleeding and who received a blood transfusion or died were identified as cases of severe gastrointestinal hemorrhage. Physical disability, cognitive function, smoking and alcohol intake habits, body mass index, blood pressure, chronic conditions, number of hospital admissions in past year and medications taken were assessed at baseline.

RESULTS

The occurrence rate of severe gastrointestinal bleeding was 10.8 per 1000 person-years (241 events/22,277 person-years). In proportional hazards regression models, compared with no disability, > or = 1 disabilities in the Rosow-Breslau scale (RR = 2.1, 95% CI = 1.5-2.9), and > or = 1 ADLs limitations (RR = 3.1, 95% CI = 2.1-4.6) independently predicted gastrointestinal hemorrhage after adjusting for age, gender, body mass index, comorbidity, number of hospital admissions, blood pressure, intake of coumarin, corticosteroids, aspirin and other nonsteroidal anti-inflammatory drugs.

CONCLUSIONS

In this prospective analysis, disability is an independent predictor of gastrointestinal hemorrhage. Further studies are needed to explain the mechanisms by which disability may cause gastrointestinal hemorrhage. Because physical disability is potentially modifiable, strategies to lower the risk of gastrointestinal bleeding should be evaluated.

The outcome of peptic ulcer haemorrhage in relation to consumption of nonsteroidal anti-inflammatory drugs or aspirin

AIM

To compare the outcome of 76 patients who presented with severe peptic ulcer haemorrhage whilst taking nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin with that of 112 patients who were not taking these drugs and who developed peptic ulcer haemorrhage over the same time period.

METHODS

The two groups of patients were managed identically and endoscopic therapy was attempted in all cases.

RESULTS

The group taking NSAIDs or aspirin tended to be older and had a higher prevalence of cardio-respiratory disease. The severity of bleeding (as assessed by the presence of shock, anaemia and endoscopic stigmata) was similar in the two groups. Outcome in terms of uncontrolled haemorrhage, rebleeding and blood transfusion requirements did not differ significantly in the two groups. The NSAID group had a significantly longer duration of admission, almost certainly attributable to a higher prevalence of co-morbid diseases.

CONCLUSIONS

Despite the deleterious effects of NSAIDs and aspirin upon renal and platelet function, the prognosis of peptic ulcer bleeding is not adversely affected by NSAID or aspirin therapy.

A cost-utility analysis of misoprostol prophylaxis for rheumatoid arthritis patients receiving nonsteroidal antiinflammatory drugs

OBJECTIVE

To determine the cost-utility of low-dose misoprostol prophylaxis in rheumatoid arthritis (RA) patients treated with nonsteroidal antiinflammatory drugs (NSAIDs).

METHODS

Prospectively collected, population-based data on 57 RA patients' preferences (obtained using the category scaling and time trade-off techniques), charge data from a consecutive, population-based cohort of 36 RA patients with NSAID-related gastric ulcer, and literature-derived probability estimates were incorporated into a decision analysis model.

RESULTS

Probabilistic sensitivity analysis using 10,000 Monte Carlo simulations demonstrated that, on average, prophylaxis resulted in modest additional costs and no additional quality-of-life benefits. At best, the incremental cost per quality-adjusted life year gained was $9,333. At worst, prophylaxis reduced quality of life. Prophylaxis was cost-saving if the ulcer complication rate was > 1.5%, or if the 3-month price of misoprostol was < or = $95.

CONCLUSION

Whereas prophylaxis may be cost-saving among high-risk NSAID users, from some patients' perspective, it reduces quality of life. Although these data may not be generalizable to other clinical populations, they illustrate the importance of incorporating patient preferences into economic evaluations.

A study of the effects of exposure misclassification due to the time-window design in pharmacoepidemiologic studies

This paper considers the effects of the time-window design on the validity of risk estimates in record linkage studies. A time-window constitutes the number of exposure days assigned to each prescription, often fixed time-intervals. Prescription information was drawn from 36 Dutch pharmacies. Persons, assuming full compliance to the dosage regimen, used NSAIDs during 58% of the 30 day window time (31% with 90 day window). This proportion ranged from 51 to 81% for different NSAIDs; from 75% for elderly to 35% for younger persons. We observed with longer windows a substantive attenuation of incidence rates of peptic ulcer therapy. Simulations also showed that the assignment of equal windows to groups with different durations of drug use can bias risk comparisons, either away from the null or towards the null. We concluded that the choice of prescription time-windows can influence the estimates of exposure risks. Time-windows should cover the period with potential excess risk and be validated.

Review article: controversies in NSAID-induced gastroduodenal damage--do they matter?

BACKGROUND

This article reviews various issues surrounding NSAID-induced gastroduodenal ulceration, about which there appear to be conflicting views and data in the literature. These issues include the size, clinical relevance and main site of the problem; when complications occur (early or late?); the relevance of non-ulcer lesions and whether adaptation is a clinically relevant phenomenon.

METHOD

A comprehensive literature search was carried out to identify relevant new data published since 1987.

RESULTS

NSAIDs are causally associated with more gastric than duodenal ulcers but their use may be associated with duodenal ulcers or complications. Erosive lesions may progress to more severe damage. The theories of early or late onset of complications during a course of NSAID therapy may not be mutually exclusive.

CONCLUSIONS

Available data indicate that NSAID ulcers are at least as dangerous as classic peptic ulcers, and result in significant morbidity and mortality which in the patient population does not appear to be significantly reduced by processes such as adaptation.

Completeness of prescription recording in outpatient medical records from a health maintenance organization

Since validity of drug data is often characterized by the agreement between questionnaire and medical record data, medical record completeness for drug therapy was evaluated. Outpatient medical records of 501 randomly selected Group Health Cooperative Health Maintenance Organization (HMO) participants known to have been dispensed a non-steroidal anti-inflammatory drug (NSAID) were reviewed for completeness. Documentation was also evaluated for indication, age, gender, location of visit, and number of visits. The NSAID was recorded in 89% of the charts reviewed. Charts with a vague/missing diagnosis were more likely to lack documentation [RR (95% CI): 20.0 (13.2-30.3)]. The data suggested that poorer documentation was related to older age [1.5 (0.9-2.5)] but not to gender, indication, location of visit, or number of visits. Presence of an indication was positively correlated to the completeness of drug documentation. According to this staff/group HMO, there may be a higher concordance between self-reported medication use and medical record data than found in previous literature.

Epidemiology of gastrointestinal damage associated with nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with significant upper gastrointestinal (GI) toxicity, with a relative risk of approximately 3. This is supported by evidence drawn from randomised controlled trials [of aspirin (acetylsalicylic acid)], cohort studies and case-control studies. The risk is increased with higher doses of medication, shorter treatment duration and concomitant corticosteroid use. Elderly patients and those with a history of GI illness are also at increased risk. Ibuprofen may be associated with a lower, and piroxicam with a higher, risk of complications. There are only preliminary data regarding an association between NSAIDs and small and large intestinal complications. Therapeutic alternatives which may confer a lower risk of significant GI toxicity include enteric-coated preparations, non-acetylated salicylates, and NSAIDs taken in conjunction with misoprostol. Epidemiological data regarding these alternatives are sparse.

Healing and prevention of NSAID-induced peptic ulcers

Non-steroidal anti-inflammatory drug (NSAID) ingestion is associated with erosions, petechiae, type C gastritis, ulceration, interference with ulcer healing, ulcer complications and injury to the small and large intestines. In the UK, NSAIDs can probably be linked to approximately 1200 deaths per year, mainly in the elderly. Inhibition of prostaglandin synthesis plays a major part in NSAID-induced gastric mucosal injury, whilst inhibition of thromboxane synthesis by platelets and impaired platelet aggregation may contribute to ulcer bleeding. There is evidence to show that the impairment of healing of gastric and duodenal ulcer that is associated with concomitant NSAID therapy can be overcome by the use of omeprazole. Acid inhibition has been shown to be effective in prophylaxis of NSAID-induced duodenal lesions. Studies on the prevention of NSAID-associated gastric lesions have indicated that ranitidine is less effective than misoprostol, but that treatment with the latter is associated with a number of side effects, principally in the gastrointestinal tract (e.g. diarrhoea). Whether omeprazole will prevent gastric and duodenal ulceration due to NSAID ingestion is the subject of ongoing research, but studies of acute ulceration have shown efficacy against erosions and microbleeding.

Variability in the risk of major gastrointestinal complications from nonaspirin nonsteroidal anti-inflammatory drugs

BACKGROUND

We have assessed the extent to which the risk of serious gastrointestinal complications from nonaspirin nonsteroidal anti-inflammatory drugs (NANSAIDs) varies with the age and sex of recipients, use of aspirin or alcohol, administration by the oral or rectal route, and dose and choice of drug.

METHODS

A case-control study was performed with prospective recruitment of cases of gastrointestinal bleeding or ulcer perforation and age- and sex-matched controls. Information on preadmission drug use obtained by structured interview.

RESULTS

Six hundred forty-four patients and 1268 controls were recruited. The odds ratio for upper gastrointestinal complications in users compared with nonusers of NANSAIDs increased with age: < or = 59 years, odds ratio 2.0; 60-79 years, odds ratio 3.0; > or = 80 years, odds ratio 4.2; and was higher in women (5.4) than in men (1.9). There was a linear dose-response curve that was steeper in women than in men. Combined exposure suggested additive risks: NANSAIDs and aspirin, odds ratio 6.7; NANSAIDs and alcohol, odds ratio 6.0 NANSAIDs by the oral route were associated with an odds ratio of 2.3, compared with 11.4 with rectal administration. Piroxicam was associated with the highest risk, odds ratio 4.8; and ibuprofen the lowest risk, odds ratio 0.7.

CONCLUSIONS

A number of factors can alter the risk of major gastrointestinal complications with NANSAIDs and need to be considered when individual prescribing decisions are made.

Non-steroidal anti-inflammatory drugs and hypertension in the elderly: a community-based cross-sectional study

1. Whether non-steroidal anti-inflammatory drug (NSAID) usage in the elderly elevates blood pressure or antagonises the blood pressure-lowering effect of antihypertensive medication is presently unknown. The primary aims of this study were to estimate the prevalence of NSAID usage, to evaluate the prescription of NSAIDs for arthritis and to determine whether NSAID usage was an independent predictor of hypertension in a large elderly community. 2. All non-institutionalised elderly (> 60 years) residents of Dubbo, NSW who attended for a baseline assessment were enrolled (1237 males, 1568 females). A questionnaire was administered and blood pressure was measured according to the Prineas protocol. The frequency of NSAID usage was determined, with stratification by age, sex, blood pressure group and history of arthritis. 3. NSAID usage was 26% overall (females 28%, males 23%), increased with age and was higher in females than males for every age group studied. Amongst patients with a past history of 'arthritis', 45% were using NSAIDs. Twelve percent were taking NSAIDs and antihypertensive medication concurrently, constituting the population at risk of an adverse drug-drug interaction. Employing a multiple logistic regression model which adjusted for several confounders in the cross-sectional analysis, NSAID usage significantly predicted the presence of hypertension (odds ratio: 1.4, 95% confidence interval: 1.1-1.7) with an attributable risk of 29%. 4. Amongst non-institutionalised elderly persons, NSAID usage may be an independent risk factor for hypertension. Considering the substantial consumption of NSAIDs by elderly patients, physicians should review their NSAID prescribing patterns for this community group.

The cost-effectiveness of misoprostol for nonsteroidal antiinflammatory drug-associated adverse gastrointestinal events

OBJECTIVE

To compare, in a Canadian health care setting, the costs and consequences of 3 strategies of misoprostol prophylaxis for osteoarthritis patients: prophylaxis for all patients taking nonsteroidal antiinflammatory drugs (NSAIDs), for no patients taking NSAIDs, and for only elderly patients (age > or = 60) taking NSAIDs.

METHODS

We designed a decision-analysis model which incorporated costs (estimated with ulcer patient profiles and medical records), review, and probabilities (estimated from a companion meta-analysis, selected literature review, and Ontario Ministry of Health Statistics). Effectiveness was defined as the number of episodes of gastric ulceration requiring hospitalization or outpatient management that were averted by each strategy.

RESULTS

On average, prophylaxis cost an additional $650 for every additional gastrointestinal event prevented. Prophylaxis for elderly NSAID users was cost saving if the ulcer complication rate in this group exceeds 1.2%, or if either the charges for outpatient ulcer treatment exceed $2,000, or the 3-month price of misoprostol is < or = $90.

CONCLUSION

Our results demonstrate that, in this setting, misoprostol prophylaxis may be highly cost effective.

Ulcer risk factors: interactions between Helicobacter pylori infection, nonsteroidal use, and age

PURPOSE

To evaluate the influence of Helicobacter pylori, nonsteroidal anti-inflammatory drug (NSAID) use, tobacco and alcohol use, age, gender, ethnic group, and the indication for endoscopy on the frequency of gastric and duodenal ulcers in patients referred for upper endoscopy.

PATIENTS AND METHODS

One thousand eighty-eight consecutive patients without prior antrectomy or active bleeding at endoscopy who were able to provide a history were interviewed prior to endoscopy, and antral biopsies were performed for H. pylori at endoscopy. Variables were tested for univariate association with duodenal or gastric ulcer and those variables with p < 0.25 were included in the logistic regression model building.

RESULTS

One hundred seven patients had duodenal ulcer, 97 had gastric ulcers, and 5 had both. Significant risk factors in the final model for duodenal ulcer were H. pylori, history of previous ulcer, male gender, bleeding, and pain at presentation (p < 0.001), whereas alcohol was associated with a decreased risk (p = 0.026). H. pylori presence (p = 0.011), aspirin use (p = 0.009), and bleeding (p = 0.012) were associated with gastric ulcer in the final model; esophageal symptoms were associated with decreased risk of gastric ulcer (p = 0.003). NSAID use was associated with gastric ulcers only in those over 55 (p < 0.05), especially whites, and in nonwhites without prior ulcer. There was no interaction between H. pylori and NSAIDs.

CONCLUSIONS

H. pylori was associated with an increased risk of duodenal and gastric ulcers. Aspirin increases the risk for gastric ulcer in patients of all ages, whereas nonaspirin, nonsteroidal use increases the risk for gastric ulcers to varying degrees in patients over age 55, depending on race and history of ulcer.

Current surgical management of duodenal ulcers

The optimal treatment of duodenal ulcer disease today requires familiarity with a variety of operative approaches. Experience and judgment are needed to select the best procedure for the individual patient presenting with a specific ulcer complication. Improved medical therapy has relegated surgery largely to the role of emergency life-saving intervention. Nonetheless, the goal of surgery remains cure of the ulcer diathesis with avoidance of postoperative side effects. Toward this end, proximal gastric vagotomy has proved itself to be the operation of choice, not only for intractable pain, but also for perforation and perhaps for bleeding in selected good-risk patients. Its efficacy in the treatment of obstructing duodenal ulcer has not been demonstrated. Modifications of proximal gastric vagotomy, including the use of laparoscopic techniques, are currently being evaluated in patients with intractable duodenal ulcer pain.

Management of gastroduodenopathy associated with use of nonsteroidal anti-inflammatory drugs

Adverse events associated with the use of nonsteroidal anti-inflammatory drugs (NSAIDs) are reported more frequently to the Food and Drug Administration than are those associated with any other group of drugs. The absolute risk for serious gastrointestinal events--in particular, ulcer bleeding, perforation, and death--is controversial; some investigators believe that an epidemic of NSAID-related complications is being experienced, whereas others suggest that the risks are being overemphasized. The management of patients who take NSAIDs regularly also remains controversial. Key unresolved issues include how best to identify those patients at particularly high risk for the development of ulcer complications and whether such patients should receive prophylactic therapy in an attempt to prevent such problems. In this review, we critically evaluate the currently available literature and present a management algorithm for the treatment and prevention of NSAID-associated gastroduodenopathy.

Pharmacoepidemiological perspectives

Parallel with increasing concerns about drug safety, the importance of drug surveillance and the application of epidemiologic techniques have grown rapidly during the past decades. The increasing use of computerized health care data facilitates the establishment of populations large enough (millions) to allow epidemiological studies. Such extensive studies are now being done routinely in North America. By the use of computerized pharmacy or billing records, drug exposure is linked to files which include diagnoses. These record-linkage systems provide "objective" drug histories for pharmacoepidemiological cohort and case-control studies and these large databases offer powerful tools for drug evaluation. A number of new drug-disease associations, many of potential importance for European populations, will be discovered through the increased use of large databases in North America. The European community needs to develop a strategy to respond to these overseas findings to protect society from either overreaction or underreaction to drug safety issues.

A prospective study of risk for peptic ulcer disease in Seventh-Day Adventists

Cross-sectional and prospective data were collected and analyzed to identify risk factors for the development of peptic ulcer disease in a population of 34,198 white, non-Hispanic Seventh-Day Adventists. On a life-style questionnaire administered in 1976, 3853 subjects reported ever having had a physician-diagnosed peptic ulcer for a lifetime prevalence of 13.5% for men and 11.0% for women. Odds ratios of greater than 2.0 (P less than 0.0001) were observed for use of "stronger pain relievers," current cigarette smoking, and history of rheumatism or other arthritis and coronary disease. For both sexes, lower but statistically significant odds ratios (P less than 0.05) were found for eating white bread, "snacking," ever having smoked cigarettes, low church involvement, poor dietary adherence, high blood pressure, rheumatoid arthritis, aspirin use, job frustration and dissatisfaction, having a "blue collar household," and having less education. During 3 years of follow-up, 154 incident cases of ulcer were identified. The average annual incidence was 1.7 per 1000. Multivariate adjusted relative risks were statistically significant for using stronger pain relievers (P less than 0.001), having rheumatic conditions (P = 0.006), and using aspirin (P = 0.013). These findings suggest that rheumatic disease and use of aspirin and stronger pain relievers are more important risk factors for development of peptic ulcer disease in certain populations than diet, life-style, or psychological or socioeconomic characteristics.

Linking prescription and patient‐identifying data: a pilot study

OBJECTIVE

To link a Pharmaceutical Benefits Scheme (PBS) prescription data set with patient-identifying data held by the Health Insurance Commission (HIC) and to then determine the prevalence of prescribing of cardiovascular drugs, non-steroidal anti-inflammatory drugs, hypnotics and minor tranquillizers, and diuretics (prescribed without other cardiovascular drugs) by age and sex in two defined populations.

DESIGN

Prescription data for a three-month period in 1985 were matched with patient-identifying information to obtain a database which included the patient's age, sex and an identifying number, for each prescription record. The percentages of the population taking a drug from each of the drug categories mentioned above were then determined and the effect of age, sex and region of residence on prescribing prevalence was investigated using logistic regression analysis.

SETTING

Two rural regions of Australia with a total population of 65,087 residents.

MEASUREMENTS AND MAIN RESULTS

Of the 101,383 prescriptions dispensed over the period 96% could be matched with HIC information. In the two regions combined, the percentages of the population taking a cardiovascular drug, non-steroidal anti-inflammatory drug, hypnotic or minor tranquilizer, or diuretic (without other cardiovascular drugs) were 10.4%, 5.8%, 3.5% and 2.5%, respectively. Prescribing rates were higher for females than males, increased with age and varied between the two regions. Approximately 5% of women aged 30-39 years were taking diuretics without other cardiovascular drugs, compared with only 0.2% of men in the same age group.

CONCLUSIONS

This pilot study illustrates the use of a patient-identified prescription database for drug utilisation review, therapeutic audit and hypothesis generation.

Nonsteroidal anti-inflammatory drugs--the clinical dilemmas

Physicians using nonsteroidal anti-inflammatory drugs (NSAIDs) are concerned that effective anti-inflammatory doses cause few gastrointestinal side effects. Among the causes of discontinuing therapy, upper gastrointestinal symptoms and the development of 'ulcer' complications are major concerns; endoscopic findings in asymptomatic users are not. Initial symptoms, poorly correlated with endoscopic findings, are relieved by anti-ulcer drugs and ameliorate with time of NSAID use in most patients. Symptoms accompanied by epigastric tenderness, or unrelieved by H2 antagonists, or resulting in cessation of NSAID therapy are more predictive of underlying ulcers. Complications probably arise in several ways, including as hemorrhages due to interference with platelet function, and as complications due to exacerbations of underlying ulcer disease or of ulcers caused by the NSAIDs. Pathogenesis and effective prophylaxis (yet to be established) may therefore vary in different patients, a clinical dilemma.

[Epidemiology and treatment of gastroduodenal lesions caused by non-steroidal anti-inflammatory agents]

The most common serious adverse reactions to nonsteroidal anti-inflammatory drugs (NSAIDs) are those affecting the gastro-intestinal tract. There is epidemiologic evidence that NSAIDs use is associated with the development of gastric ulcer and with upper gastrointestinal bleeding and perforation of both duodenal and gastric ulcers. The individual risk is low but given the widespread use of NSAIDs, the number of cases is large with appreciable morbidity and mortality. The main risk factors are age above 65, previous ulcer history and treatment with several NSAIDs. Prophylactic therapy is justified in high risk patients. Synthetic prostaglandin misoprostol has been shown to reduce significantly the frequency of gastric ulcer in patients on NSAIDs. By contrast, H2 receptor blockade with ranitidine has been demonstrated to prevent duodenal but not gastric ulcers. Gastric and duodenal ulcers associated with NSAIDs appear to heal on H2 receptors antagonists and prostaglandins even if NSAIDs are continued. However, large gastric ulcer may heal slowly over 8 to 12 weeks. The place of omeprazole remains to be determined.

The problems and pitfalls of NSAID therapy in the elderly (Part II)

The elderly are most susceptible to pharmacokinetic drug interactions between various NSAIDs and anticoagulants, sulphonylurea hypoglycaemic agents, certain anticonvulsants, methotrexate, digoxin, aminoglycosides and lithium. Pharmacodynamic interactions between some NSAIDs and antihypertensive drugs, anticoagulants, sulphonylurea agents and other NSAIDs are also potentially significant in the elderly. Despite the finding that mean therapeutic responses of large groups of patients have been generally equivalent for the wide range of NSAIDs studied thus far, it is also apparent that marked variability exists in the response of individual patients to different NSAIDs. Subsequent dosage increments may predispose 'nonresponders' and some less sensitive 'responders' to toxicity from NSAIDs. This interindividual variability in response to NSAIDs may be contributed to by the differing physicochemical properties of NSAIDs, physician prescribing habits and patient expectations, variations in NSAID pharmacokinetics, and the differing effects of NSAIDs other than their common ability to inhibit prostaglandin synthesis. The principles for drug prescribing in the elderly are no different from those that should be applied to the prescribing of medication in any patient. The clinician should strive to make a diagnosis and should avoid treating symptoms in isolation. Critical assessment of the indication for prescribing NSAID therapy must include consideration of the available effective and safe alternatives. If an NSAID is commenced the lowest effective dose should be the desired goal, but after an appropriate trial it is acceptable clinical practice to employ an alternative NSAID. There is no justification for combination NSAID therapy. The progress of each patient must be carefully monitored, particularly during the first few months of treatment, while periodic review of the ongoing need for the NSAID is essential.

Using a claims database to investigate drug-induced Stevens-Johnson syndrome

In order to explore a priori hypotheses about drug-induced Stevens-Johnson Syndrome (SJS), a case-control study was initiated using data from COMPASS, a computerized data base consisting of Medicaid claims data. The records of 3.8 million patients in five U.S. states were searched to identify patients with an inpatient diagnosis of ICD-9-CM code 695.1 (erythema multiforme-EM). Out of the total of 367 cases that were identified, primary medical records for 249 were sought and 128 (51.4 per cent) of these were obtained. The remainder could not be obtained because: in 36 (29.8 per cent) the hospital refused to provide medical records; in 33 (27.3 per cent) there were transcription errors; in 20 (16.5 per cent) the state could not translate the identification number, primarily because the patients lost Medicaid eligibility too long before our request; in 27 (22.3 per cent) the hospital could not locate the patient's record; and in 5 (4.1 per cent) there were other reasons. Of those with a medical record, 121 (94.5 per cent) had a skin diagnosis and 109 (85.2 per cent) had a diagnosis compatible with ICD-9-CM code 695.1 specified on their discharge summary. However, in 35 (27.3 per cent) an expert reviewer felt that the discharge diagnosis was incorrect. In 50 (39 per cent) the computer diagnosis was incorrect. Only 19 (14.8 per cent) were judged by the expert reviewer to truly have Stevens-Johnson Syndrome, and an additional 37 (28.9 per cent) were judged to have erythema multiforme minor. Thus, the computerized diagnosis agreed very well with the diagnoses specified on the discharge summary. However, EM is frequently misdiagnosed, ICD-9-CM code 695.1 contains multiple other diagnoses which are not EM, and much of hospitalized EM is EM minor. Thus, studies of SJS cannot be performed except in patients whose medical records are available.

Ranitidine prevents duodenal ulcers associated with non-steroidal anti-inflammatory drug therapy

The results of four similarly designed, randomized, double-blind, placebo-controlled studies conducted to evaluate ranitidine as prophylaxis for NSAID-associated damage are reviewed. A total of 673 patients receiving therapeutic dosages of NSAIDs for arthritic or musculoskeletal conditions also received either ranitidine 150 mg twice daily (n = 343) or placebo (n = 330) for four weeks (two studies) or eight weeks (two studies). Endoscopic grading of mucosal lesions was based on a modified Lanza scoring system. All patients had normal baseline endoscopies. After four weeks of treatment a significant protective effect against duodenal mucosal lesions including duodenal ulcers (three studies) and gastric mucosal lesions including gastric ulcers (one study) was observed in patients who received ranitidine compared with those who received placebo. A meta-analysis of the four studies confirmed that significantly fewer patients receiving ranitidine than placebo developed duodenal ulcers (1% vs. 6%, P = 0.01). Endoscopic data at eight weeks from the two longer-term studies showed that duodenal ulcers occurred in ranitidine- and placebo-treated patients at a rate of 1% (2/137) vs. 8% (10/126) (P = 0.02), respectively, in one trial, and 0% (0/57) vs. 8% (4/49) (P = 0.02), respectively, in the other trial. No protective effect in the stomach was evident at eight weeks. We conclude that ranitidine is effective in preventing NSAID-associated duodenal ulcers and may be appropriate prophylaxis for certain high-risk patients.

Drug-related admissions to a department of medical gastroenterology. The role of self-medicated and prescribed drugs

Three hundred and twenty-eight consecutive patients admitted to a department of medical gastroenterology were evaluated in a high-intensity study of drug-related hospitalizations (DRH). The drug events considered were adverse drug reaction and dose-related therapeutic failures (DTF). With regards to the 'definite' and 'probable' drug events, DRHs accounted for 26 admissions (7.9%; 95% confidence interval (CI), 5.2-11.4%), and with the additional inclusion of 'possible' drug events DRHs accounted for 39 admissions (11.9%; CI, 8.6-15.9%). Of these, five and seven admissions, respectively, were caused by DTF. Patients admitted because of drug events took significantly more drugs than others. An evaluation of the circumstances of the 26 'definite' or 'probable' DRH showed none to be 'definitely avoidable', 6 to be 'possibly avoidable', and 20 to be 'not avoidable' by efforts from the prescribing physicians. Gastroduodenal lesions causally related to non-steroidal anti-inflammatory drug (NSAID) or aspirin use accounted for 17 of the definite, probable, or possible DRHs (44%). Only 1 of the 11 cases related to NSAID use was rated as possibly avoidable by efforts from the health service personnel. In 13 cases self-medication with aspirin played a substantial role in the DRH. Self-medication was largely characterized by poor indication, uncontrolled use, polypharmacy, treatment of epigastric pain with aspirin, and the patient's unawareness of potential adverse reactions. This suggests the need for intensified information to the public concerning the adverse effects of aspirin and NSAID.

Upper gastrointestinal bleeding in relation to previous use of analgesics and non-steroidal anti-inflammatory drugs. Catalan Countries Study on Upper Gastrointestinal Bleeding

To assess the risk of upper gastrointestinal bleeding associated with the use of individual non-narcotic analgesics and non-steroidal anti-inflammatory drugs (NSAIDs), a multicentre study of 875 cases of upper gastrointestinal bleeding and 2682 hospital controls was done. With control for confounding factors, the overall odds ratio estimate for aspirin taken at least once during the week before the first symptom was 7.2 (95% confidence interval 5.4-9.6). Non-aspirin NSAIDs associated with upper gastrointestinal bleeding were diclofenac (7.9 [4.3-14.6]), indomethacin (4.9 [2.0-12.2]), naproxen (6.5 [2.2-19.6]), and piroxicam (19.1 [8.2-44.3]). Paracetamol, propyphenazone, and dipyrone did not increase the risk. A previous history of gastrointestinal bleeding or peptic ulcer did not greatly affect odds ratio estimates, which differed according to sex and were higher for younger than for older patients. However, the incidence of upper gastrointestinal bleeding was higher among the elderly.

Nonsteroidal anti-inflammatory drug toxicity: increased risk in the elderly

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in the therapy of rheumatic diseases, especially in older patients. The toxicity profile of NSAIDs includes gastrointestinal (GI) toxicity, renal dysfunction and hepatic disease. Altered drug pharmacology in older patients may be a factor in their increased risk for drug toxicity. Elderly patients appear to be at greatest risk for symptomatic GI toxicity, including ulceration and even major GI bleeding. Central nervous system toxicity, characterized by dizziness, headaches, mood alteration and confusion, and renal dysfunction have also been reported to occur more commonly among elderly patients. Hepatic dysfunction is a rare NSAID-induced toxicity, but older patients are often at greatest risk for serious hepatic disease. Understanding the patient's underlying physiologic condition, concomitant drug therapy and the kinetics of the NSAID being used is critical to the safe administration of these agents to elderly individuals.

Utilization patterns of non-steroidal anti-inflammatory drugs in an open Dutch population

Non-steroidal anti-inflammatory drugs represent an important drug class in ambulatory care. A utilization study among half a million persons showed that 8.6% could be identified as having used one or more non-steroidal anti-inflammatory drugs (excluding salicylates) in 1987. Data were drawn from a representative sample of pharmacy records which comprise full medication histories of individual patients. Overall utilization of non-steroidal anti-inflammatory drugs was 10.8 defined daily doses/(1000 persons.day). Approximately three quarters of the patients are 'incidental' users and receive non-steroidal anti-inflammatory drugs for a relatively short time (30 days or less). Patients who were identified as 'regular' (31-210 days of therapy) and 'heavy' (greater than 210 days of therapy) users, accounted for 21.2% respectively 4.8% of all users. 'Heavy' users are responsible for 17.3% of all non-steroidal anti-inflammatory drug prescriptions. Especially the elderly and females are prone to be 'heavy' users. Five drugs account for 90.4% of all prescriptions (diclofenac, ibuprofen, naproxen, piroxicam, indomethacin). A total of 71.1% of the patients with more than one prescription for non-steroidal anti-inflammatory drugs switched in therapy. There are two classes of concomitant drug use especially relevant with respect to detecting non-steroidal anti-inflammatory drugs-associated risks: H2 blockers and antacids (belonging to anatomical therapeutic and chemical anatomic class A) and diuretics (belonging to anatomical therapeutical chemical anatomic class C). More than half of the 'heavy' users showed concomitant use of drugs in these classes.

Risk of acute upper gastrointestinal bleeding in patients with ulcerative disease and treatment with non-steroidal anti-inflammatory drugs (NSAIDs). Results from the Comprehensive Hospital Drug Monitoring Berne (CHDM)

The hospital prevalence rate for upper gastrointestinal ulcerative disease in 28,531 inpatients consecutively admitted in two teaching hospitals in the Comprehensive Hospital Drug Monitoring (CHDM) in Berne, from 1974 to 1985, was 2.2% (1.8% for gastric or duodenal ulcer, and 0.4% for erosive gastritis). This was based on the evaluation of 634 patients after exclusion of the subgroup of patients with hepatic cirrhosis or upper gastrointestinal neoplasia. After exclusion of patients on anticoagulant therapy (n = 73), 561 (= 100%) patients could be further studied. Of them, 33.3% (n = 187) were found to have been exposed to non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, within 21 days prior to confirmation of the diagnosis. The observed relative risk (RR) of developing a substantial acute upper gastrointestinal bleeding (Hb less than 10 g/100 ml for men, and less than 9 g/100 ml for women, or a decrease in Hb of more than 25%) was 1.61 when patients exposed to NSAIDs (n = 187) were compared to patients not exposed to those drugs (n = 374). Although there was no significant sex difference overall, the RR for gastrointestinal bleeding differed considerably in the various age-groups; it was elevated in men under 40 years (RR = 2.86) and in women over 60 years of age (RR = 1.89), as compared to the mean RR of 1.61.

Epidemiology in peptic ulcer disease. Current status and future aspects

Peptic ulcer incidence is declining. A decreased prevalence of smokers together with other factors have contributed to this change. The widespread use of non-steroidal anti-inflammatory drugs (NSAID) has increased the incidence of ulcer in the older population and serious complications, such as perforation and bleeding, have been observed especially in older women. Helicobacter pylori infection is virtually always present in duodenal and gastric ulcer and active chronic gastritis, but not prepyloric ulcer. The fact that this organism is not eradicated with the use of most drugs for peptic ulcer may explain the high rate of recurrence in ulcer disease since relapse rates are reported to be considerably lower when H. pylori is eradicated. In a substantial number of patients peptic ulcers are silent. These fall into two categories: the regular ulcer patient with relapses that heal spontaneously and rarely cause problems, and older patients without prior ulcer disease receiving NSAID treatment, presenting with a life-threatening complication as the first indication of ulcer disease. Despite all the new knowledge of peptic ulcer disease presented, the questions still outnumber the answers; it is therefore suggested that future research focus on the role of NSAIDs and H. pylori.

Pharmaco-epidemiological perspectives

Parallel with increasing concerns about drug safety, the importance of drug surveillance and the application of epidemiologic techniques have grown rapidly during the past decades. The increasing use of computerized health care data facilitates the establishment of populations large enough (millions) to allow epidemiological studies. Such extensive studies are now being done routinely in North America. By the use of computerized pharmacy or billing records, drug exposure is linked to files which include diagnoses. These record-linkage systems provide 'objective' drug histories for pharmaco-epidemiological cohort and case-control studies and these large data bases offer powerful tools for drug evaluation. A number of new drug-disease associations, many of potential importance for European populations, will be discovered through the increased use of large data bases in North America. The European community needs to develop a strategy to respond to these overseas findings to protect the society from either overreaction or underreaction to drug safety issues.

Epidemiologic evidence on the association between peptic ulceration and antiinflammatory drug use

Adverse effects associated with nonsteroidal antiinflammatory drug treatment are reported more commonly to regulatory authorities than the adverse effects of any other form of treatment. Epidemiologic evidence in general suggests a doubling or quadrupling of the risk of ulcer complications or death in recipients of such treatment. The risk appears to be related to increasing age, but no other associated factor has yet been identified. It is uncertain whether individuals with preexisting ulcer are at special risk or whether treatment predisposed equally to ulcer and ulcer complications, and there is no clear evidence that the nature of the disability leading to nonsteroidal antiinflammatory drug treatment influences the risk of gastrointestinal complications.

Side-effects of non-steroidal anti-inflammatory drugs

Despite a continuing lack of good quality epidemiological studies, our knowledge of the side-effects of NSAIDs has advanced in recent years. The most important reactions are those which are related predictably to the pharmacology of the drugs and these need to be considered whenever a NSAID is prescribed, particularly for patients who can be identified as belonging to high-risk groups. The important reactions are: 1. Gastrointestinal damage, which is now known to extend to some degree from the oesophagus to the rectum, although the acid contact areas of the stomach and duodenum are the most important. Although the studies have produced heterogeneous results, NSAIDs probably double or triple the risk of an individual developing serious gastrointestinal haemorrhage or perforation. The risk increases with age and previous history of ulceration, and, in communities with particularly high use of NSAIDs, the drugs may account for up to 30% of all cases of ulcer complications. 2. Renal syndromes, of which functional renal impairment is the most important. This may precipitate cardiac failure, and hyperkalaemia is an additional hazard. Antagonism of the action of diuretics may contribute to the fluid retention, and antagonism of antihypertensive therapy is probably quite common and may result in additional unnecessary therapy. Patients at risk of functional renal impairment from NSAIDs can be identified readily and in these subjects the drugs have to be used with great care and with appropriate monitoring. 3. Respiratory effects, in particular acute bronchospasm in subjects with a history of aspirin sensitivity. NSAIDs should be used with caution in asthmatics, and patients purchasing NSAIDs without prescriptions need to be warned of these effects. Other uncommon serious reactions include hepatocellular damage, acute interstitial nephritis, agranulocytosis and aplastic anaemia, Stevens-Johnson syndrome and toxic epidermal necrolysis. These are unpredictable reactions which generally need not be considered before prescribing. However, in patients who present with any of these conditions, NSAIDs, because of their wide use, should always be considered as a possible cause.