Ethnic differences in the risks of adverse reactions to drugs used in the treatment of psychoses and depression: a systematic review and meta-analysis.

<bold>Background: </bold>Factors such as age, sex and disease state alter a patient's susceptibility to adverse drug reactions (ADRs). Ethnicity may also alter the risk of an ADR.<bold>Objective: </bold>To review the evidence for ethnic differences in susceptibility to adverse reactions to drugs used to treat psychoses and depression.<bold>Data Sources: </bold>We searched MEDLINE (from 1951), EMBASE (from 1974), and PsycINFO (from 1950) to March 2006.<bold>Study Selection: </bold>Studies were included if there was a mention of ethnicity, ethnic or racial groups and a description of a procedure to investigate ADRs specifically or a description of ADRs that were a result of drugs in therapeutic use. Studies selected by any two reviewers were retained if they referred to drugs used in the treatment of psychoses and related disorders or antidepressant drugs. Of 124 studies describing ADRs to antipsychotics or antidepressants, 51 reported data from different ethnic groups.<bold>Data Extraction: </bold>Data were extracted independently from those studies selected for inclusion by two reviewers, using a standard data extraction form. Studies were assessed for bias in order to determine the quality of the study.<bold>Data Synthesis: </bold>In a pooled analysis of patients treated with antipsychotics, the relative risk (RR) of tardive dyskinesia in Black compared with White patients was 1.03 (95% CI 0.85, 1.24); the RR of extrapyramidal symptoms in East Asian compared with non-East Asian patients was 1.38 (95% CI 1.11, 1.72); the RR of hyperglycaemia in Black compared with non-Black patients was 1.55 (95% CI 0.95, 2.53); and the RR of diabetes mellitus in non-White compared with White patients was 1.35 (95% CI 0.95, 1.92). It was impossible to perform pooled analysis of data from studies investigating antidepressants due to insufficient data.<bold>Conclusions: </bold>We found limited evidence of ethnic differences in the risk of ADRs. The clinical implications of these results remain unclear because of confounding factors. Further progress will require improved recruitment of patients from different ethnic groups and an established consensus on how to define ethnicity. [ABSTRACT FROM AUTHOR]