A Retrospective Review of Serious Adverse Drug Reaction Reports in the Nigerian VigiFlow Database from September 2004 to December 2016.

Background: Adverse drug reactions (ADRs) are a source of concern in healthcare as they negatively affect patients. Serious adverse drug reactions (SADRs) have an even greater impact on patients and the system in terms of morbidity and financial burden. The establishment of National Pharmacovigilance Centers (NPCs) has enhanced ADR reporting in Africa. The Nigerian Pharmacovigilance Centre has been collecting ADR reports using VigiFlow since 2004.

Objective: The aim of this study was to identify and analyze SADR reports in the Nigerian VigiFlow database in order to profile the patients with SADRs, the medicines most implicated, system organ classes (SOCs) affected, outcome of such reactions, including fatalities, and ADR reporting trends over the years. We also looked at the data elements provided in the reports as a proxy measure of report quality.

Method: We retrospectively assessed all individual case safety reports (ICSRs) received by the NPC in Nigeria and entered into VigiFlow as SADR reports between September 2004 and December 2016. We defined SADR as any untoward reaction to any medicine dose that resulted in death, required in-patient hospitalization or prolongation of existing hospitalization, resulted in congenital anomaly, persistent or significant disability/incapacity or was life-threatening. The suspected SADRs were analyzed at the Medical Dictionary for Regulatory Activities SOC and Preferred Term levels.

Results: A total of 11,222 ICSRs were entered into VigiFlow during the study period, of which 298 (3%) were classified as SADR reports. Adults were the most affected (244/282; 87%). The median number of medicines per report was 3 (interquartile range = 2-4.75). Nevirapine (36/336; 11%), as a single entity, was the most reported medicine. Human immunodeficiency virus (HIV) infection affected 128/232 (55%) of those with SADRs. There was no statistically significant association between the number of reactions per report and sex of the patients (p = 0.280), their age groups (p = 0.670), or the number of medicines per report (p = 0.640). Hospitalization was the most frequently cited reason for classifying a report as serious (151/276; 53%) and death was reported in 48 cases (48/283; 17%). Based on the SOC, skin and subcutaneous tissue disorders (139/550; 25%) was the most affected, while anemia (55/550; 10%) was the most reported specific reaction. A substantial number of patients (107/256; 42%) either recovered fully or were recovering from the SADRs. The number of SADR reports received varied by year with no consistent trend.

Conclusion: There is under-reporting of ADRs in the Nigerian VigiFlow database, particularly SADRs and those involving pediatric and geriatric age groups. Given that over half of the SADR reports involved antiretroviral drugs, it is imperative to increase the surveillance of ADRs related to this class of drugs through regular clinical assessment of reports and provision of feedback on the findings to healthcare providers. Direct consumer reporting should also be encouraged as a means of increasing ADR reporting.