Validity of vascular trauma codes at major trauma centres.

BACKGROUND: The use of administrative databases in vascular injury research has been increasing, but the validity of the diagnosis codes used in this research is uncertain. We assessed the positive predictive value (PPV) of International Classification of Diseases, tenth revision (ICD-10), vascular injury codes in administrative claims data in Ontario. METHODS: We conducted a retrospective validation study using the Canadian Institute for Health Information Discharge Abstract Database, an administrative database that records all hospital admissions in Canada. We evaluated 380 randomly selected hospital discharge abstracts from the 2 main trauma centres in Toronto, Ont., St.Michael's Hospital and Sunnybrook Health Sciences Centre, between Apr. 1, 2002, and Mar. 31, 2010. We then compared these records with the corresponding patients' hospital charts to assess the level of agreement for procedure coding. We calculated the PPV and sensitivity to estimate the validity of vascular injury diagnosis coding. RESULTS: The overall PPV for vascular injury coding was estimated to be 95% (95% confidence interval [CI] 92.3-96.8). The PPV among code groups for neck, thorax, abdomen, upper extremity and lower extremity injuries ranged from 90.8 (95% CI 82.2-95.5) to 97.4 (95% CI 91.0-99.3), whereas sensitivity ranged from 90% (95% CI 81.5-94.8) to 98.7% (95% CI 92.9-99.8). CONCLUSION: Administrative claims hospital discharge data based on ICD-10 diagnosis codes have a high level of validity when identifying cases of vascular injury. LEVEL OF EVIDENCE: Observational Study Level III.

CONTEXTE: L'utilisation des bases de données administratives pour la recherche sur les lésions vasculaires est en hausse, mais la validité des codes diagnostiques utilisés dans ces recherches est incertaine. Nous avons évalué la valeur prédictive positive (VPP) des codes de lésions vasculaires de la dixième édition de la Classification internationale des maladies (CIM-10) qui figurent dans une base de données administrative ontarienne. MÉTHODES: Nous avons réalisé une étude de validation rétrospective à partir de la base de données de l'Institut canadien d'information sur la santé (ICIS) sur les congés des patients, une base de données administrative qui enregistre toutes les hospitalisations au Canada. Nous avons évalué 380 congés hospitaliers de 2 grands centres de traumatologie de Toronto, en Ontario, soit l'Hôpital St. Michael's et le Centre des sciences de la santé Sunnybrook, entre le 1er avril 2002 et le 31 mars 2010. Nous avons ensuite comparé ces dossiers aux dossiers hospitaliers des patients correspondants pour vérifier la concordance des codes attribués aux interventions. Nous avons calculé la VPP et la sensibilité pour estimer la validité des codes diagnostiques appliqués aux lésions vasculaires. RÉSULTATS: La VPP globale pour les codes de lésions vasculaires a été estimée à 95% (intervalle de confiance [IC] de 95% 92,3­96,8). Parmi les groupes de codes attribués aux lésions affectant le cou, le thorax, l'abdomen, les membres supérieurs et inférieurs, la VPP a varié de 90,8 (IC de 95% 82,2­95,5) à 97,4 (IC de 95% 91.0­99,3), tandis que la sensibilité a varié de 90% (IC de 95% 81,5­94,8) à 98,7% (IC de 95% 92,9­99,8). CONCLUSION: Les données administratives sur les congés hospitaliers basées sur les codes diagnostiques de la CIM 10 ont un degré de validité élevé pour ce qui est des lésions vasculaires. NIVEAU DE PREUVE: Étude d'observation Niveau III.

Cardiovascular outcomes after a change in prescription policy for clopidogrel.

BACKGROUND: Drug-reimbursement policies may have an adverse effect on patient outcomes if they interfere with timely access to efficacious medications for acute medical conditions. Clopidogrel in combination with aspirin is the recommended standard of care for patients receiving coronary stents to prevent thrombosis. We examined the population-level effect of a change by a Canadian provincial government in a pharmacy-benefits program from a prior-authorization policy to a less restrictive, limited-use policy on access to clopidogrel among patients undergoing percutaneous coronary intervention (PCI) with stenting after acute myocardial infarction. METHODS: We conducted a population-based, retrospective, time-series analysis from April 1, 2000, to March 31, 2005, of all patients 65 years of age or older with acute myocardial infarction who underwent PCI with stenting in Ontario, Canada. The primary outcome was the composite rate of death, recurrent acute myocardial infarction, PCI, and coronary-artery bypass grafting at 1 year, with adjustment for sex and age. The secondary outcome was major bleeding. RESULTS: The rate of clopidogrel use within 30 days after hospital discharge following myocardial infarction increased from 35% in the prior-authorization period to 88% in the limited-use period. The median time to the first dispensing of a clopidogrel prescription decreased from 9 days in the first period to 0 days in the second period. The 1-year composite cardiovascular outcome significantly decreased from 15% in the prior-authorization group to 11% in the limited-use group (P=0.02). Rates of bleeding in the two groups did not change. CONCLUSIONS: The removal of a prior-authorization program led to improvement in timely access to clopidogrel for coronary stenting and improved cardiovascular outcomes.

Narcotic analgesic utilization amongst injured workers: using concept mapping to understand current issues from the perspectives of physicians and pharmacists.

BACKGROUND: Work-related injuries result in considerable morbidity, as well as social and economic costs. Pain associated with these injuries is a complex, contested topic, and narcotic analgesics (NA) remain important treatment options. Factors contributing to NA utilization patterns are poorly understood. This qualitative study sought to characterize the factors contributing to NA utilization amongst injured workers from the perspectives of physicians and pharmacists. METHODS: The study employed concept mapping methodology, a structured process yielding a conceptual framework of participants' views on a particular topic. A visual display of the ideas/concepts generated is produced. Eligible physicians and pharmacists (n = 22) serving injured workers in the province of Ontario (Canada) were recruited via purposive sampling, and participated in concept mapping activities (consisting of brainstorming, sorting, rating, and map exploration). Participants identified factors influencing NA utilization, and sorted these factors into categories (clusters). Next, they rated the factors on two scales: 'strength of influence on NA over-utilization' and 'amenability to intervention'. During follow-up focus groups, participants refined the maps and discussed the findings and their implications. RESULTS: 82 factors were sorted into 7 clusters: addiction risks, psychosocial issues, social/work environment factors, systemic-third party factors, pharmacy-related factors, treatment problems, and physician factors. These clusters were grouped into 2 overarching categories/regions on the map: patient-level factors, and healthcare/compensation system-level factors. Participants rated NA over-utilization as most influenced by patient-level factors, while system-level factors were rated as most amenable to intervention. One system-level cluster was rated highly on both scales (treatment problems - e.g. poor continuity of care, poor interprofessional communication, lack of education/support for physicians regarding pain management, unavailability of multidisciplinary team-based care, prolonged wait times to see specialists). CONCLUSIONS: Participants depicted factors driving NA utilization among injured workers as complex. Patient-level factors were perceived as most influential on over-utilization, while system-level factors were considered most amenable to intervention. This has implications for intervention design, suggesting that systemic/structural factors should be taken into account in order to address this important health issue.

Social licence and the general public's attitudes toward research based on linked administrative health data: a qualitative study.

BACKGROUND: Both the research literature and headline news stories indicate that the public cares about how their health data are used. The objective of this study was to learn more about the general public's attitudes toward users and uses of linked administrative health data held by ICES in Ontario, Canada. METHODS: Eight focus groups, with a total of 65 members of the general public, were conducted in urban and northern settings in Ontario, Canada, in 2015 and 2017 using qualitative market research panels established by a market research/public opinion research firm. RESULTS: Three major themes emerged: (a) the need for assurance about privacy and security, (b) general support for research based on linked administrative health data with some conditions and (c) mixed and more negative reaction when there is private sector involvement. Two minor themes were also derived from the data: (a) low knowledge and understanding of how linked administrative health data are used for research and (b) mixed views on the need to obtain consent when health data do not include identifying information. INTERPRETATION: The public generally supports research based on linked administrative health data, but there is no blanket approval. Researchers and organizations that hold health data should engage with members of the public to understand and address their concerns about privacy and security and to ensure that research is aligned with social licence, particularly where there is private sector involvement.

Cardiovascular disease and hypertension risk in living kidney donors: an analysis of health administrative data in Ontario, Canada.

BACKGROUND: Knowledge of any harm associated with living kidney donation guides informed consent and living donor follow-up. Risk estimates in the literature are variable, and most studies did not use a healthy control group to assess outcomes attributable to donation. METHODS: We observed a retrospective cohort using health administrative data for donations which occurred in Ontario, Canada between the years 1993 and 2005. There were a total of 1278 living donors and 6359 healthy adults who acted as a control group. Individuals were followed for a mean of 6.2 years (range, 1-13 years) after donation. The primary outcome was a composite of time to death or first cardiovascular event (myocardial infarction, stroke, angioplasty, and bypass surgery). The secondary outcome was time to a diagnosis of hypertension. RESULTS: There was no significant difference in death or cardiovascular events between donors and controls (1.3% vs. 1.7%; hazard ratio 0.7, 95% confidence interval 0.4-1.2). Donors were more frequently diagnosed with hypertension than controls (16.3% vs. 11.9%, hazard ratio 1.4, 95% confidence interval 1.2-1.7) but were also seen more often by their primary care physicians (median [interquartile range] 3.6 [1.9-6.1] vs. 2.6 [1.4-4.3] visits per person year, P<0.001). CONCLUSIONS: Based on administrative data, the risk of cardiovascular disease was unchanged in the first decade after kidney donation. The observed increase in diagnosed hypertension may be due to nephrectomy or more blood pressure measurements received by donors in follow-up and requires prospective study.

Suboptimal use of statin therapy in elderly patients with atherosclerosis: a population-based study.

BACKGROUND: Current evidence suggests that statin use plays an important role in improving adverse cardiovascular outcomes in patients with atherosclerosis. However, limited population-based data are available on use of statin therapy in these patients in Canada. We sought to study trends in statin use to treat these patients in Ontario during a 10-year period. METHODS: We conducted a population-based cross-sectional time series analysis between April 1, 1995, and March 31, 2004, using health care data from Ontario, Canada. RESULTS: During the study period, 343,154 elderly patients with atherosclerosis were identified. Of these, 235,615 (68.7%) had coronary artery diseases (CAD), 115,012 (33.5%) had cerebrovascular disease (CVD), and 23,886 (7.0%) had peripheral arterial disease (PAD). About 46% were women, and mean patient age was 77.1 (SD, 7.5) years. During the study period, the percentage of patients treated with a statin in each group increased considerably, from 9.8% to 55.3% in all atherosclerotic patients (P < .01), from 11.8% to 61.2% in CAD patients (P < .01), from 5.3% to 41.2% in CVD patients (P < .01), and from 6.8% to 43.3% in PAD patients (P < .01). During the entire study period, the percentage of statin users was lowest among PAD and CVD patients, followed by patients with both a history of PAD and CVD. CONCLUSION: The use of statin therapy in elderly patients with symptomatic atherosclerosis has increased substantially during the past decade, but many patients remain untreated. The suboptimal use is greatest among patients with PAD or CVD, or both, and lowest in patients with CAD. Given the heightened risk of cardiovascular adverse outcomes in patients with atherosclerosis, these data have important and immediate implications.

Comparison of provincial prescription drug plans and the impact on patients' annual drug expenditures.

BACKGROUND: Reimbursement for outpatient prescription drugs is not mandated by the Canada Health Act or any other federal legislation. Provincial governments independently establish reimbursement plans. We sought to describe variations in publicly funded provincial drug plans across Canada and to examine the impact of this variation on patients' annual expenditures. METHODS: We collected information, accurate to December 2006, about publicly funded prescription drug plans from all 10 Canadian provinces. Using clinical scenarios, we calculated the impact of provincial cost-sharing strategies on individual annual drug expenditures for 3 categories of patients with different levels of income and 2 levels of annual prescription burden ($260 and $1000). RESULTS: We found that eligibility criteria and cost-sharing details of the publicly funded prescription drug plans differed markedly across Canada, as did the personal financial burden due to prescription drug costs. Seniors pay 35% or less of their prescription costs in 2 provinces, but elsewhere they may pay as much as 100%. With few exceptions, nonseniors pay more than 35% of their prescription costs in every province. Most social assistance recipients pay 35% or less of their prescription costs in 5 provinces and pay no costs in the other 5. In an example of a patient with congestive heart failure, his out-of-pocket costs for a prescription burden of $1283 varied between $74 and $1332 across the provinces. INTERPRETATION: Considerable interprovincial variation in publicly funded prescription drug plans results in substantial variation in annual expenditures by Canadians with identical prescription burdens. A revised pharmaceutical strategy might reduce these major inequities.

Challenges to evidence-based prescribing in clinical practice.

Although there appears to be widespread support of evidence-based medicine as a basis for rational prescribing, the challenges to it are significant and often justified. A multitude of factors other than evidence drive clinical decision-making, including patient preferences and social circumstances, presence of disease-drug and drug-drug interactions, clinical experience, competing demands from more pressing clinical conditions, marketing and promotional activity, and system-level drug policies.

Asthma mortality in portugal : impact of treatment with inhaled corticosteroids and leukotriene receptor antagonists.

OBJECTIVE: To determine whether the use of inhaled corticosteroids or leukotriene receptor antagonists (LTRAs) has had an impact on asthma mortality in Portugal during the period 1991-2001. METHODS: A population-based ecological study was conducted for the period 1991-2001. Yearly asthma death rates were computed for all ages. Data on sales of inhaled corticosteroids and LTRAs were obtained and expressed in defined daily doses (DDDs)/year. The association between the yearly rate of asthma deaths and consumption of these medications was estimated using Poisson regression. RESULTS: The rate of asthma death decreased steadily from 39.4 per million inhabitants in 1991 to 14.2 in 2001. At the same time, the use of inhaled corticosteroids in the population increased from 5.8 to 22.2 million DDDs per year. The adjusted rate ratio of asthma death was 0.85 (95% CI 0.78, 0.92) for every additional 5 million DDDs of inhaled corticosteroids per year and 0.84 (95% CI 0.70, 1.02) for every additional 5 million DDDs of LTRAs per year. CONCLUSION: The increasing use of inhaled corticosteroids and leukotriene receptor antagonists during the 1990s in Portugal appears to have contributed to the reduction in asthma mortality in that country.

Rates and patterns of chronic obstructive pulmonary disease exacerbations.

BACKGROUND: Acute exacerbations of chronic obstructive pulmonary disease (COPD) are believed to be a common occurrence in patients with COPD and are known to be associated with considerable morbidity. OBJECTIVE: To describe the frequency of treated COPD exacerbations in a large population-based cohort. SUBJECTS AND METHODS: A cohort of newly treated patients with COPD was formed from the administrative databases of Saskatchewan Health. The outcome was the occurrence of all moderate or severe exacerbations from 1990 to 1999. Exacerbations were defined in three ways: dispensing of a prescription for a systemic antibiotic; dispensing of both a prescription for an antibiotic and a prescription for an oral corticosteroid on the same day; and requiring a hospitalization with a primary discharge diagnosis of COPD. RESULTS: There were 5645 patients who entered the COPD cohort between 1990 and 1997, of whom 4453 experienced at least one exacerbation requiring treatment during follow-up. The overall rate of acute exacerbations was 1.12/person-year. It was constant across all age groups, and was similar in both men and women (1.13/person-year versus 1.11/person-year, respectively). The rate of exacerbations was highest in the first trimester of therapy for the disease (1.39/person-year) and stabilized thereafter at 1.04 exacerbations/person-year. CONCLUSIONS: The results indicate that in a population-based cohort of patients with COPD, the average rate of exacerbations was 1.12/person-year. Men and women had similar rates of exacerbations.

Authors' self-declared financial conflicts of interest do not impact the results of major cardiovascular trials.

OBJECTIVES: This study assessed whether the results of major, potentially practice-altering cardiovascular trials were influenced by the authors' self-declared financial conflicts of interest (FCOI). Secondary objectives included assessment of trial outcomes by source of funding, by FCOI subtype, and by trial endpoints. BACKGROUND: Financial conflicts of interest, ubiquitous in cardiovascular medicine because of significant investigator-industry collaborations, potentially can influence trial outcomes. METHODS: A MEDLINE search was performed using the MeSH term cardiovascular disease limited to randomized controlled trials and clinical trials published from January 1, 2000, through April 15, 2008, in 3 high-impact journals. Two reviewers independently abstracted data from the published article. Chi-square tests, Fisher exact tests, and multivariate logistic regression were used to assess the associations between FCOI and study characteristics and between FCOI and trial outcomes. RESULTS: Of the 550 articles reviewed, 51.1% satisfied FCOI criteria, including at least one of the following: stock ownership, employee, speaker's bureau, and consultant). Of the 538 articles providing sponsorship information, 34.6% reported funding solely by nonprofit organizations, 48.3% reported funding solely by industry, and 17.1% reported funding by a combination. Prevalence of FCOI significantly increased with level of industry funding: 21.5% (none), 50.0% (shared), 75.0% (industry solely, n = 281, p < 0.0001). However, no differences in reporting of favorable results were detected when articles were analyzed by self-declared FCOI (60.5% vs. 59.5% in those with and without, odds ratio: 1.04, p = 0.81). This result was upheld in multivariate analysis. CONCLUSIONS: Authors' self-declared FCOI and source of funding do not seem to impact outcomes in major cardiovascular clinical trials.

Fabry's disease: a prospective multicenter cohort study in young adults with cryptogenic stroke.

BACKGROUND: Stroke in young adults is etiologically diverse and may represent a diagnostic challenge remaining cryptogenic in one-fourth of cases. Limited information is available on the prevalence of Fabry's disease, a treatable multisystem inherited lysosomal storage disorder, and disability in young patients with cryptogenic stroke. DESIGN AND METHODS: The Canadian Fabry Stroke Screening Initiative (CFSSI) is a prospective multicenter cohort study of young adults (age 18-55) presenting with an ischemic stroke, transient ischemic attack, or intracerebral haemorrhage of unknown etiology to stroke centres across Canada. Diagnosis of Fabry's disease is made by direct DNA analysis of blood samples for α-galactosidase gene mutations or polymorphisms. Demographics, clinical information, and investigations including brain Magnetic Resonance Imaging (MRI) are collected. Functional neurological assessment includes neurological examination, the National Institutes of Health (NIH) stroke scale, modified Rankin scale, and the Barthel index. A follow-up interview is conducted by telephone or in person approximately six-months after the index stroke/transient ischemic attack/intracerebral haemorrhage to determine patient outcomes, quality of life, and patient use of medications. MAIN OUTCOME: Prevalence of positive DNA mutation or single nucleotide polymorphism screens for Fabry's disease as a proportion of total cryptogenic stroke. Secondary outcomes include incident risk of new or recurrent vascular event at six-months, discharge disposition, disability at six-months as measured by the modified Rankin scale, mean time from symptoms onset to the definite etiological diagnosis, and length of hospital stay. CONCLUSION: This study constitutes the first initiative to determine the prevalence of a positive screen for Fabry's disease in young adults with stroke in Canada. Moreover, the Canadian Fabry Stroke Screening Initiative will provide information on recurrent vascular events, disability at six-months (modified Rankin scale), and disposition in this understudied population.

Antipsychotic therapy and short-term serious events in older adults with dementia.

BACKGROUND: Antipsychotic therapy is widely used to treat behavioral problems in older adults with dementia. Cohort studies evaluating the safety of antipsychotic therapy generally focus on a single adverse event. We compared the rate of developing any serious event, a composite outcome defined as an event serious enough to lead to an acute care hospital admission or death within 30 days of initiating antipsychotic therapy, to better estimate the overall burden of short-term harm associated with these agents. METHODS: In this population-based, retrospective cohort study, we identified 20 682 matched older adults with dementia living in the community and 20 559 matched individuals living in a nursing home between April 1, 1997, and March 31, 2004. Propensity-based matching was used to balance differences between the drug exposure groups in each setting. To examine the effects of antipsychotic drug use on the composite outcome of any serious event we used a conditional logistic regression model. We also estimated adjusted odds ratios using models that included all covariates with a standard difference greater than 0.10. RESULTS: Relative to those who received no antipsychotic therapy, community-dwelling older adults newly dispensed an atypical antipsychotic therapy were 3.2 times more likely (95% confidence interval, 2.77-3.68) and those who received conventional antipsychotic therapy were 3.8 times more likely (95% confidence interval, 3.31-4.39) to develop any serious event during the 30 days of follow-up. The pattern of serious events was similar but less pronounced among older adults living in a nursing home. CONCLUSIONS: Serious events, as indicated by a hospital admission or death, are frequent following the short-term use of antipsychotic drugs in older adults with dementia. Antipsychotic drugs should be used with caution even when short-term therapy is being prescribed.

Does statin therapy decrease the risk for bleeding in patients who are receiving warfarin?

PURPOSE: Recent observations in patients with atrial fibrillation who are receiving warfarin suggest that concomitant treatment with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) decreases the risk for bleeding. METHODS: We conducted a population-based, nested case-control study using the linked administrative databases of Ontario, Canada, to assess whether statin use decreases the risk of bleeding in warfarin users. Eligible patients were Ontario residents, age 66 years or more, with atrial fibrillation who were prescribed warfarin between April 1, 1994, and December 31, 2001. Patients were followed until hospitalization for upper gastrointestinal or intracranial bleeding, study end (March 31, 2002), discontinuation of warfarin, or death. Cases were matched to controls by age and sex. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between bleeding and statin use. RESULTS: We identified 79,207 warfarin users with atrial fibrillation. There were 1518 cases with an upper gastrointestinal or intracranial bleed and 15,100 matched controls without bleeding. Long-term (>/=1 year) statin use was associated with a lower risk for any bleeding (OR=0.80; 95% CI, 0.66-0.97). However, there was no association between bleeding and recent (<6 months) statin use (OR=1.04; 95% CI, 0.74-1.48) or statin use of any duration (OR: 0.91; 95% CI, 0.77-1.07), suggesting potential confounding of the association between statin use and bleeding by a health-user effect. CONCLUSION: Long-term statin use may be associated with a decreased risk for bleeding in warfarin users with atrial fibrillation. Additional research is needed to further explore this putative association.

Angiotensin receptor blockers vs. angiotensin converting enzyme inhibitors and acute coronary syndrome outcomes in elderly patients: a population-based cohort study (UMPIRE study results).

Inhibitors of the renin-angiotensin system remain a cornerstone of cardiovascular pharmacotherapy. Although angiotensin converting enzyme inhibitors (ACEIs) have been demonstrated to afford cardiovascular risk reduction in patients with atherosclerosis and preserved left ventricular function, at the present time it is unclear if angiotensin receptor blockers (ARBs) exert similar benefits. We performed a population-based comparative study to compare the rates of hospital admission for acute coronary syndromes between users of ARBs relative to the use of ACEIs. A retrospective cohort study using population-based administrative databases in Ontario, Canada covering over 1.4 million residents age 65 years and older with access to universal healthcare coverage was conducted. We compared the hospital admission for acute coronary syndromes (ACS) among patients initiated on ARBs as compared to propensity-score matched patients started on ACEIs from 1999 through 2002, using a 3:1 (ACEI:ARB) matching strategy. Each individual was observed for up to 2 years. The primary outcome of interest was an ACS event, defined as the composite of hospital admission for myocardial infarction and/or unstable angina. During over 71,000 person-years of follow-up, we observed 1,295 hospitalizations for ACS. Relative to ACEI users (n = 49,037), rate of hospitalizations for ACS was similar in patients initiated on ARBs (n = 16,456) (adjusted relative risk [aRR] 0.89, 95% confidence interval [CI] 0.76-1.04. Pre-specified secondary analysis, performed in patients with atherosclerosis, diabetes, and heart failure, also revealed no difference in rates of myocardial infarction and acute coronary syndromes in users of ARBs compared to ACEIs (adjusted relative risk, diabetes: 0.79, 95% CI 0.58-1.07; heart failure: 0.84, 95% CI 0.59-1.20; atherosclerosis: 0.85, 95% CI 0.70-1.04). These data represent the first and largest population based comparative evaluation of ACEI and ARBs on hospitalizations for ACS among new users of each therapy. Our findings suggest that ARBs offer similar reduction in acute coronary syndrome outcomes in elderly patients with atherosclerosis, diabetes or heart failure. These data have important clinical implications, especially since patients over the age of 65 represent the largest users of risk reduction therapy.

Prevalence of self-medication in rural areas of Portugal.

OBJECTIVES: To study the prevalence of self-medication among pharmacy customers in rural areas of Portugal, to assess possible predictors of self-medication and to find out whether there was a seasonal dependence in the purchase of drugs for self-medication. METHOD: A cross-sectional study during four different periods of a year was conducted. Community pharmacies of rural areas of Portugal were invited to participate and pharmacists were asked to recruit one person every hour during the opening hours and administer a questionnaire. Drugs dispensed were classified according to the Anatomical Therapeutic Chemical Classification system up to the second level. MAIN OUTCOME MEASURE: Prevalence of self-medication is defined as the percentage of patients acquiring a medicine that was not prescribed (written) or recommended (orally) by a physician. RESULTS: The prevalence of self-medication was 21.5%. Main therapeutic groups acquired for self-medication were "other alimentary tract and metabolism products" (A16; proportion acquired for self-medication= 75.0%), "throat preparations" (R02; 74.7%), "antiemetics and antinauseants" (A04; 70.0%), "cough and cold preparations" (R05; 56.5%), and "nasal preparations" (R01; 50.0%). Variables found to be predictors of self-medication were age, type of health professional or person consulted when a mild health problem occurred, time elapsed since last visit to the physician and time waited between setting an appointment and the actual visit. Seasonality seemed to occur for only "cough and cold preparations", for "dermatologicals" and for "anti-inflammatory and anti-rheumatic products". CONCLUSION: In rural Portugal about one fifth of the pharmacy customers engaged in self-medication. However, further research should be made to address appropriateness of self-medication.