Validation of suicide and self‐harm records in the C linical P ractice R esearch D atalink

Abstract

Aims: The UK C linical P ractice R esearch D atalink (CPRD) is increasingly being used to investigate suicide‐related adverse drug reactions. No studies have comprehensively validated the recording of suicide and nonfatal self‐harm in the CPRD. We validated general practitioners' recording of these outcomes using linked O ffice for N ational S tatistics (ONS) mortality and Hospital Episode Statistics (HES) admission data. Methods: We identified cases of suicide and self‐harm recorded using appropriate R ead codes in the CPRD between 1998 and 2010 in patients aged ≥15 years. Suicides were defined as patients with R ead codes for suicide recorded within 95 days of their death. I nternational C lassification of D iseases codes were used to identify suicides/hospital admissions for self‐harm in the linked ONS and HES data sets. We compared CPRD‐derived cases/incidence of suicide and self‐harm with those identified from linked ONS mortality and HES data, national suicide incidence rates and published self‐harm incidence data. Results: Only 26.1% (n = 590) of the ‘true’ (ONS‐confirmed) suicides were identified using R ead codes. Furthermore, only 55.5% of R ead code‐identified suicides were confirmed as suicide by the ONS data. Of the HES‐identified cases of self‐harm, 68.4% were identified in the CPRD using R ead codes. The CPRD self‐harm rates based on R ead codes had similar age and sex distributions to rates observed in self‐harm hospital registers, although rates were underestimated in all age groups. Conclusions: The CPRD recording of suicide using R ead codes is unreliable, with significant inaccuracy (over‐ and under‐reporting). Future CPRD suicide studies should use linked ONS mortality data. The under‐reporting of self‐harm appears to be less marked.