Validity of World Health Organisation prescribing indicators in Namibia's primary health care: findings and implications

Objective: World Health Organization/ International Network of Rational use of Drugs (WHO/INRUD) indicators are widely used to assess medicine use. However, there is limited evidence on their validity in Namibia’s primary health care (PHC) to assess the quality of prescribing. Consequently, our aim was to address this. Design, setting, participants and interventions: An analytical cross-sectional survey design was used to examine and validate WHO/INRUD indicators in outpatient units of two PHC facilities and one hospital from 1st February 2015 to 31st July 2015. The validity of the indicators was determined using two-by-two tables against compliance to the Namibian standard treatment guidelines (NSTG). The receiver operator characteristics for the WHO/INRUD indicators were plotted to determine their accuracy as predictors of compliance to agreed standards. A multivariate logistic model was constructed to independently determine the prediction of each indicator. Main outcomes and results: Out of 1243 prescriptions; compliance to NSTG prescribing in PHCs was sub-optimal (target was >80%). Three of the four WHO/INRUD indicators did not meet Namibian or WHO targets: antibiotic prescribing, average number of medicines per prescription and generic prescribing. The majority of the indicators had low sensitivity and/or specificity. All WHO/INRUD indicators had poor accuracy in predicting rational prescribing. The antibiotic prescribing indicator was the only covariate that was a significant independent risk factor for compliance to NSTGs. Conclusion: WHO/INRUD indicators showed poor accuracy in assessing prescribing practices in PHCs in Namibia. There is need for appropriate models and/or criteria to optimize medicine use in PHCs in the future