Methods
We reviewed cases of ADR previously identified in a study including 300 adult inpatients. These patients were recruited from January 26 to March 6, 2015 in surgical and medical wards of a general 500-bed university hospital located in Belo Horizonte, Southeastern Brazil. The study was approved by the Research Ethics Committee of the Universidade Federal de Minas Gerais. All participants signed a patient consent statement. In the present study, ADR was defined as “a response to a medicinal product which is noxious and unintended and which occurs at doses normally used in man for the prophylaxis, diagnosis or therapy of disease or for the restoration, correction or modification of physiological function”, according to WHO.[8, 9] The methods used to identify ADR were described elsewhere.[9]
Three healthcare professionals acted as judges to adjudicate, independently, each ADR reported in the study according causality categories of ADR. The professionals had experience in assistance and research. They had different academic background, including a nurse (Judge A), a pharmacist (Judge B) and a physician (Judge C). Standardized forms were evaluated by the judges and included the following information: patient’s data (age, sex, diagnosis, type of comorbidities, laboratory data, daily clinical data and drug therapy) and ADR data (onset/end of clinical manifestation, history of allergies, administered doses, drug interactions, suspected drugs to cause ADR and time of its use).
Expert adjudication process consisted in the evaluation of cases by each judge, separately, followed by the record of his/her judgment in an instrument developed specifically for this study. ADR were classified into six categories (certain, probable, possible, unlikely, conditional, unassessable), according to WHO-UMC criteria and based on individual expertise. Additionally, the judge was required to register the suspected drug(s) to have caused ADR.
ADR causality was also evaluated using Naranjo algorithm which is a method consisting in ten yes/no questions.[5] They were evaluated in this study consensually by two clinical pharmacists with pharmacovigilance expertise. Preventability of ADR was assessed by the judges, using Schumock and Thornton method, adapted from Shajahanet al. [6, 7]