Causality and preventability assessment of adverse drug reactions and adverse drug events of antibiotics among hospitalized patients: A multicenter, cross-sectional study in Lahore, Pakistan

Background and objectives Adverse drug events (ADEs) are the fifth leading cause of death and thus responsible for a large number of hospital admissions in all over the globe. This study was aimed to assess the antibiotics associated preventability of ADEs and causality of adverse drug reactions (ADRs) among hospitalized patients. Methods A prospective, cross-sectional, observational study was conducted in four tertiary care public sector hospitals of Lahore, Pakistan. Study population consisted of hospitalized patients who were prescribed with one or more antibiotics. Data were collected between 1 st January, 2017 and 31 st June, 2017 from 1,249 patients (384 patients aged ≤ 18 years and 865 patients aged >18 years). Schumock and Thornton scale was used to assess the preventability of the ADEs. Medication errors (MEs) that caused preventable ADEs were assessed by MEs tracking form while Naranjo score was used to evaluate the causal relation of ADRs with the antibiotics. Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp.) and Microsoft Excel (MS Office, 2010) were used for data analysis. Results 2,686 antibiotics were prescribed to 1,249 patients. Among them, fluoroquinolones (11.8%), macrolides (11.6%) and cephalosporins (10.9%) were the most frequently prescribed antibiotics. The most affected organ system by antibiotics associated ADEs was gastrointestinal tract. A total of 486 ADEs were found. The preventability assessment revealed that most of the ADEs (58.4%) were preventable (43.6% of the ADEs were definitely preventable while 14.8% were probably preventable) and caused by MEs including wrong drug (40.1%) and monitoring errors (25.0%), during the stage of physician ordering (22.2%) and patient monitoring (21.1%). The errors were caused due to non-adherence of policies (38.4%) and lack of information about antibiotics (32%). Most of the non-preventable ADEs or ADRs among adults and children were “probable” (35.5%) and “possible” (35.8%), respectively. Logistic regression analysis revealed that ADEs were significantly less among females (OR = 0.047, 95%CI = 0.018–0.121, p-value = <0.001), patients aged 18–52 years (OR = 0.041, 95%CI = 0.013–0.130, p-value = <0.001), tuberculosis patients (OR = 0.304, 95%CI = 0.186–0.497, p-value = <0.001), patients with acute respiratory tract infections (OR = 0.004, 95%CI = 0.01−0.019, p-value = <0.001) and among the patients prescribed with 2 antibiotics per prescription (OR = 0.455, 95%CI = 0.319–0.650, p-value = <0.001). Conclusion According to preventability assessment most of the ADEs were definitely preventable and caused by MEs due to non-adherence of policies and lack of information about antibiotics. The causality assessment of non-preventable ADEs showed that most of the ADRs were probable and possible.