Aim—To determine the appropriate size of risk windows in both exposed and unexposed sub‐cohorts.

EDITOR—The Information in Practice article by Majeed et al provided important insights into what can and cannot be obtained from prescribing analysis and cost (PACT) data.1 Their conclusion that the addition of the NHS number to prescriptions would not be feasible until all general practices are fully computerised, however, is incorrect. Since 1990 the Medicines Monitoring Unit has been adding the NHS number (formerly the community health number in Scotland) to all prescriptions for the Tayside region of Scotland (400 000 people) …

Introduction: The relationship between topically applied non-steroidal anti-inflammatory drugs (TNSAIDs) and gastroduodenal complications is uncertain. The aim of this study was to investigate the hypothesis that TNSAIDs are associated with upper gastrointestinal bleeding and perforation (UGIBP) using a record-linkage database containing all hospital event and dispensing data between 1989 – 1992 in a population of approximately 400 000 people.

This cohort study examined the relationship between newly prescribed NSAIDs (none in the previous six months) and upper gastrointestinal hemorrhage and perforation in Tayside, Scotland. Exposure was classified by prescription duration. The study population consisted of the population of Tayside. A Comparator Group was chosen at random (within age and sex strata). Two hundred re-sampled comparator groups were created. Statistical analyses were carried out by Poisson regression (repeated for each of the re-samples). The analyses controlled for age, sex, prior hospitalization for upper gastrointestinal events, prior endoscopy, and the use of ulcer healing drugs. There were 78,191 subjects in the NSAID group, and 78,207 in each of the comparator groups. The increased risk with NSAIDs was only apparent for subjects without a history of upper gastrointestinal events; univariate rate ratio = 2.76 (1.90, 4.01). The final, re-sampled estimate of NSAID risk was rate ratio = 2.48 (1.87, 3.29).

The relationship between non-steroidal anti-inflammatory drugs and colitis is uncertain. The aim of this study was to evaluate the association between use of NSAIDs and colitis using a record-linkage database. This database contained prescribing and hospitalisation data for the study population of 319 465 people resident in the region since January 1989.

Aim: To examine the relationship between new NSAID exposure and validated upper gastrointestinal haemorrhage (UGIH), controlling for prior UGI diagnoses (UGID), prior endoscopy (PE) and ulcer healing drugs in the previous 6 months (UHDP) and during the study (UHDD).

BACKGROUND: To evaluate the relation between non-steroidal anti-inflammatory drugs (NSAIDs) and colitis due to inflammatory bowel disease. METHODS: A case-control study was conducted using a prospectively constructed, record linkage database containing hospital event and dispensed drug data (1989-93). The study population consisted of 319,465 people resident in Tayside in January 1989, and still resident (or dead) in October 1994. RESULTS: Of the 785 patients admitted to hospital as emergencies with colitis between July 1989 and June 1993, 200 fulfilled the case criterion of colitis due to inflammatory bowel disease. A further 1198 persons were used as community controls. Odds ratios were calculated for three exposure periods (current, recent, and past exposure). The overall odds ratios (with 95% confidence intervals) for current and recent exposure to NSAIDs were 1.77 (1.01 to 3.10) and 1.93 (1.20 to 3.09) respectively. Current and recent exposure to NSAIDs was also associated for incident cases, with odds ratios of 2.96 (1.32 to 6.64) and 2.51 (1.13 to 5.55). There was a trend for recent exposure among non-incident cases. CONCLUSION: The use of NSAIDs may be associated with an increased risk of emergency admission to hospital for colitis due to inflammatory bowel disease, particularly among patients with no previous history.

Objectives: To determine the profile of risk of upper gastrointestinal toxicity during continuous treatment with, and after cessation of, non-steroidal anti-inflammatory drugs.Design: Cohort study with a prospectively constructed, population based, record linkage database containing details of exposure to all community dispensed non-steroidal anti-inflammatory drugs and also all admissions to hospital for upper gastrointestinal diagnoses.Setting: The population of Tayside, Scotland.Subjects: 52 293 subjects aged 50 and over who received one or more non-steroidal anti-inflammatory between 1 January 1989 and 31 December 1991 and 73 792 subjects who did not receive one during the same period (controls).Main outcome measures: Admission to hospital for upper gastrointestinal bleeding and perforation, and admission for other upper gastrointestinal diagnoses.Results: About 2% of the non-steroidal anti-inflammatory cohort were admitted with an upper gastrointestinal event during the study period compared with 1.4% of controls. The risk of admission for upper gastrointestinal haemorrhage and perforation was constant during continuous non-steroidal anti-inflammatory exposure and carried over after the end of exposure. The results were similar for admissions for all upper gastrointestinal events.Conclusion: This study provides evidence that non-steroidal anti-inflammatory toxicity persists with continuous exposure. There seems to be carryover toxicity after the end of prescribing. These findings have implications for the management of patients requiring non-steroidal anti-inflammatory drugs.

A recent study using patient recall has suggested that use of non-steroidal anti-inflammatory drugs is associated with an increased risk of appendicitis.

Recent evidence from both experimental and epidemiological studies has suggested that non-steroidal anti-inflammatory drugs (NSAIDS) and aspirin may be associated with reduced incidence of colo-rectal cancer (CRCA). The aim was to evaluate the relationship between CRCA and prior use of NSAIDs and aspirin.

Depression is a common psychiatric disorder in general practice.'There is consensus that antidepressants should be given in sufficient dose and for sufficiently long if treatment is to be effective.2Tricyclic antidepressants carry warnings about their use in patients with cardiac diseases, and they have well known anticholiner- gic effects that could cause predictable toxicity.Selective serotonin uptake inhibitors are thought to be devoid of such effects.We studied the use and safety of antidepressant drugs in the community, with reference to their labelled warnings. Patients, methods, and resultsWe studied patient specific dispensed prescribing' for antidepressant drugs and admissions to hospital for possible adverse effects over 14 months using a record linkage database that covers the population of Tayside, Scotland (about 400 000 subjects).4The dose and duration of use of antidepressants was determined, as was the number of subjects who had labelled contrain- dications to and cautions against taking tricyclic anti- depressants.Overall, 20 195 patients received 85 315 prescriptions for an antidepressant drug (14 988 patients received tricyclic antidepressants, 3571 received selective serotonin reuptake inhibitors, and 1636 received both).In comparison with published guidelines,2 tricycic antidepressants were generally given in subtherapeutic doses (10 804 (72%) subjects received only subtherapeutic doses, 1125 (7%) therapeutic or both doses, and 3059 (21%) unknown doses).Selective serotonin reuptake inhibitors tended to be given in therapeutic doses (281 (8%) received

INTRODUCTION:Scottish Morbidity Record (SMR1) data are coded by trained clerical staff from case records and discharge summaries. They form the basis of many strategic NHS decisions. Their accuracy for upper gastrointestinal (UGI) diagnosis is unknown and the study was undertaken to assess this accuracy in Tayside.METHOD:Patients who fulfilled the following criteria were identified using a record-linkage pharmacoepidemiological database, and their case records retrieved: over 50 years of age, had encashed at least one prescription for a non-steroidal anti-inflammatory drug at a Tayside pharmacy and who had SMR1 records containing one or more symptom/diagnosis codes between January 1989 and December 1991. Medically qualified staff were trained to examine case records and to code UGI diagnoses. They searched the case records for every UGI SMR1 entry for these patients from 1980-1992 and produced re-coded diagnoses (RCD) for each hospital event (admission and discharge), using all the data available in the case records. They also abstracted data on the clinical presentation, investigations and management of patients. Each event was then examined by a single medically qualified researcher who compared the original SMR1 codes with the RCDs.RESULTS:2,101 patients had a total of 3,764 events in 1989-1991. 317 events were either day case procedures or elective surgery or the case records were not found. They were therefore excluded. Of the remainder, the SMR1 and RCD codes were judged equivalent in 1,608 events (46.6%). However, 1,005 SMR1 events (29.2%) contained a symptom code but no diagnosis code and the remaining 834 (24.2%) were judged suboptimal for other reasons. Of those with a symptom code only, 406 could not be improved upon and were transformed into RCD symptom codes only, 435 were assigned symptom and diagnostic RCDs and 164 were assigned diagnostic RCDs only. In the other 834 events, 279 had one or more diagnoses missing, 425 had one or more diagnoses inaccurate, 23 had both missing and inaccurate diagnoses and 107 were not UGI. Thus 1,433 (41.6%) of UGI SMR1 events could be more accurately coded. Examination of investigation data revealed that coding inaccuracy was not due to diagnostic procedures being carried out after admission.CONCLUSION:UGI SMR1 data were satisfactory in about half of all events. In about a quarter there were symptom codes but no satisfactory diagnosis codes, whilst in another quarter the data were inaccurate. These findings have implications for health care activities and research that use these data.

This was an observational study of efficacy and resource utilisation over three years in a cohort of 917 patients who received at least one prescription for an oral antibiotic between January and March 1989 in a large rural primary care health centre in Tayside, Scotland. Three thousand, six hundred and sixty three prescriptions were issued (2286 to females) for; 1502 upper respiratory tract infections, 419 lower respiratory tract infections, 441 urinary tract infections, 177 skin and soft tissue infections, 97 gynaecological infections, 103 cases of acne and 71 other infections. Excluding acne, 14% of infections required more than one antibiotic to achieve a successful outcome. The highest success rates for antibiotics were amoxycillin (92%) and penicillin V (92%) in upper respiratory tract infections, erythromycin (90%) in lower respiratory tract infections and co-trimoxazole (83%) in urinary tract infections. The most cost-effective antibiotics were penicillin V for upper respiratory tract infection, erythromycin for lower respiratory tract infection and co-trimoxazole for urinary tract infection. Varying the value placed on general practitioners' time did not change the rank order of antibiotic cost-effectiveness. The efficacy and cost-effectiveness of the treatment of acute infections in primary care varies considerably with the antibiotic used as first choice. More expensive antibiotics might be justified in cost-effectiveness terms if they had high cure rates in clinical practice.

BACKGROUND:There is controversy as to the relative safety of fenoterol and salbutamol. No differences have been found in the relative cardiac beta 1/beta 2 receptor activity of inhaled fenoterol and salbutamol in normal subjects. These initial findings have been extended by comparing the respective potencies of equivalent doses by weight of fenoterol and salbutamol in asthmatic subjects, in terms of airways and systemic responses.METHODS:Eighteen asthmatic patients of mean (SD) age 40 (14) years and a forced expiratory volume in one second (FEV1)% predicted of 56 (14)% (1.97 (0.66)1) were randomised to inhale fenoterol (100 micrograms/puff or 200 micrograms/puff), salbutamol, or placebo (100 micrograms/puff or 200 micrograms/puff) on three separate days. Dose-response curves were constructed using cumulative doses of 100 micrograms, 200 micrograms, 400 micrograms, 1000 micrograms, 2000 micrograms, and 4000 micrograms, and airways and systemic responses were measured 20 minutes after each dose with 40 minute increments. Dose ratios for the relative potency of fenoterol versus salbutamol were calculated from the dose-response curves using regression analysis of parallel slopes.RESULTS:There was no difference in bronchodilator potency between fenoterol and salbutamol (as median dose ratio): FEV1 1.1 (95% CI 0.4 to 4.6). In contrast, dose ratios for systemic responses showed that fenoterol was more potent than salbutamol: serum potassium 3.7 (95% CI 2.0 to 6.0), tremor 5.7 (95% CI 1.4 to 10.2), heart rate 1.6 (95% CI 1.0 to 2.3). At a conventional dose of 200 micrograms the only difference in response between the two drugs was observed for tremor (as mean difference): 0.23 log units (95% CI 0.06 to 0.41 log units).CONCLUSIONS:There was no difference in the bronchodilator potency between fenoterol and salbutamol on a microgram equivalent basis. In contrast, systemic potency was greater with fenoterol, although this difference was not clinically relevant at conventional dosages up to 200 micrograms.

Objective-To evaluate the relation between topically applied non-steroidal anti-inflammatory drugs and upper gastrointestinal bleeding and perforation.Design-A case-control study with 1103 patients admitted to hospital for upper gastrointestinal bleeding or perforation between January 1990 and December 1992 (cases). Two different control groups were used, with six community controls and with two hospital controls for each case. Previous exposure to topical and oral non-steroidal antiinflammatory drugs and ulcer healing drugs was assessed.Study population-The population of 319465 people who were resident in Tayside and were registered with a Tayside general practitioner between January 1989 and October 1994. A record linkage database containing all data on hospital events and dispensed drugs between 1989 and 1992 was used for this population.Main outcome measures-Unadjusted and adjusted odds ratios of exposure in those admitted to hospital compared with controls.Results-Significant unadjusted associations were detected between all three classes of drug and upper gastrointestinal complications. The significant association detected for topical non-steroidal anti-inflammatory drugs was no longer evident in analyses which adjusted for the confounding effect of concomitant exposure to oral anti-inflammatories and ulcer healing drugs (odds ratio=1.45; 95% confidence interval 0.84 to 2.50 with community controls; 1.06; 0.60 to 1.88 with hospital controls).Conclusion-In this study topical non-steroidal anti-inflammatory drugs were not significantly associated with upper gastrointestinal bleeding and perforation after adjustment for the confounding effects of concomitant use of oral anti-inflammatories and ulcer healing drugs.