Adverse Drug Reaction Onsets in Uganda’s VigiBase®: Delayed International Visibility, Data Quality and Illustrative Signal Detection Analyses

Abstract

Introduction: Developing countries can improve their pharmacovigilance systems by analysing their own medication safety data. Objective: The aims of this study were to characterize Uganda’s reported adverse drug reaction (ADR) onsets in 2012–2015 that were registered on VigiBase® by 31 December 2017, to document delays in international visibility and the influence of covariates on this delay from ADR onsets in 2013 + 2014, to examine data quality, and to illustrate analytical approaches for safety data, particularly for patients receiving antiretroviral therapy (ART). Methods: International delay was defined as elapsed time from complete ADR onset date to entry date on VigiBase®, with covariates examined using Cox proportional hazards regression. Simple random sampling was used to locate the paper-based ADR forms for data quality assurance. Disproportionality for signal detection focused on serious singleton ADR onsets in patients receiving ART. Results: Uganda’s VigiBase® had 1018 patient entries with complete ADR onset dates: 260 in 2012, 293 in 2013, 305 in 2014 and 160 in 2015. Only 16% (154/953) of ADR onsets in 2012–2015 were in patients aged < 20 years for whom randomly sampled ADR forms were less fully completed; 87% (889/1018) comprised a singleton sign/symptom; half were serious. Median delay from ADR onset to international visibility was 11 months for ADR onsets in 2013 + 2014, and longest for healthcare professionals other than pharmacists and physicians. Disproportionality for serious ADR onsets in patients receiving ART included anaemia with zidovudine, renal impairment with tenofovir, Stevens–Johnson syndrome with nevirapine and skin rash with efavirenz. Conclusions: Barely one ADR onset per day was registered on VigiBase® from those submitted to Uganda’s National Pharmacovigilance Centre during 2012–2014; only one in six was from patients aged < 20 years. Paediatric pharmacovigilance requires more emphasis in Uganda. Delays from reported ADR onset to international visibility on VigiBase® need to reduce dramatically. Quality assurance revealed rectifiable data entry deficits. Signal detection performed well for patients receiving ART.