Nationwide survey of subjectively reported adverse drug reactions in Sweden.

BACKGROUND

Adverse drug reactions (ADRs) and the safety of drugs continue to be widely discussed. However, information on the prevalence of subjectively experienced ADRs (SADRs) and their subsequent burden in the general population is largely lacking.

OBJECTIVE

To analyze, from an epidemiologic perspective, SADRs with respect to occurrence and health status.

METHODS

A cross-sectional mail survey to a random national sample in Sweden of inhabitants aged 18-84 years was conducted; 61% (N = 4875) of the sample answered the questionnaire. Self-reported SADRs occurring during a 2-week period of using prescription, over-the-counter (OTC), or herbal drugs were classified according to Meyler's classification of ADRs. Self-perceived health status was assessed with a visual analog scale graded from 0 (worst possible health/death) to 1 (perfect health).

RESULTS

SADRs were reported by 6.4% of the total study sample, 10.2% of the 2851 users of prescription drugs, 1.0% of the 2862 users of OTC drugs, and 0.1% of the 1352 users of herbal drugs. Of the total sample, 3.3% reported SADRs of the nervous system, 2.6% of the gastrointestinal system, and 0.6% of the cardiovascular system. Users of prescription drugs with SADRs reported a mean health status score of 0.655, while those who did not report SADRs scored 0.744. Among users of OTC and herbal drugs, the corresponding scores were 0.720 and 0.818, respectively. Those in the population who did not use any drugs rated their health status as 0.846.

CONCLUSIONS

Both the prevalence of SADRs and the magnitude of the decrease in subjective health status in respondents experiencing them reflect the importance of individual subjective perceptions for public health. However, in a cross-sectional study like this, causal relationships cannot be firmly established. Further, other factors, such as comorbidity or disappointment with treatment outcomes, could be associated with the decrease in health status.