The validity of explicit indicators of prescribing appropriateness

Objective. To assess, from the perspective of UK hospital doctors, the content validity and operational validity of a set of 14 previously developed explicit indicators of the appropriateness of long-term prescribing started during a hospital admission. Method. A combination of data extraction from medical records and qualitative interviews with a maximum variability sample of hospital doctors. Participants. The indicators were applied to 132 new prescriptions, intended for long-term use, prescribed for 61 patients; 36 doctors, of various grades, were purposively selected for interview. Results. Appropriate prescribing was viewed as prescribing that was indicated, necessary, evidence based (using a broad meaning of 'evidence') and of acceptable cost and risk-benefit ratio. These concepts applied to individual drugs for individual patients, rather than at a more general, public health level. Where drugs had failed an indicator, rationales were explored. Often, it was missing data in the medical notes that had resulted in the drug failing the indicator. Conclusions. The 14 indicators were considered to have content validity, reflecting all aspects of appropriate prescribing discussed by the doctors. Their operational validity was less clear-cut, due to the lack of necessary data in the medical notes. This has implications for the use of explicit indicators for assessing prescribing appropriateness, as these hospital doctors did not consider that the data required for objective, systematic assessment of prescribing would ever be recorded in hospital medical notes.