Patterns and outcomes of empirical antimicrobial use in elderly outpatients: A pilot observational study from North India

Introduction: Despite the rampant use of antimicrobials in health-care settings, the safety and clinical outcome data of antimicrobials are scarce in the elderly population. The main aim of this study is to assess the prescription pattern, therapeutic gains, and adverse reactions resulting out of antimicrobial use in elderly outpatients. Subjects and Methods: This was a prospective observational study conducted for 7 months from June 2019 to December 2019 in elderly patients visiting the geriatric outpatient department of a tertiary hospital of North India. Primary outcomes included clinical improvement as well as the incidence and type of adverse drug reactions (ADRs) observed with antimicrobial use. Results: Of 110 participants recruited, 107 were assessed for clinical outcomes. The common indications of antimicrobial use were lower respiratory tract infection (48.6%), urinary tract infection (18.7%), and worm infestations (14%). Macrolides (57%) and beta-lactams (43%) were the commonly prescribed individual antimicrobials. Outcome-wise, clinical improvement was seen in 91.3%, 88.5%, and 14.3% of patients receiving beta-lactams, macrolides, and antiprotozoals, respectively. ADRs occurred in 17.7% of participants and gastrointestinal disturbance was the commonly reported ADR. Beta-lactams and macrolides were responsible for the majority of ADRs, in 19.6% and 13.1% of participants, respectively. No association of antimicrobial-associated clinical responses or ADRs was observed with demographics and underlying comorbidities. Conclusions: Elderly patients with respiratory tract infections showed improvement with empirical extended-spectrum beta-lactams and azithromycin therapy. The response was suboptimal to empirically selected antiprotozoal therapy. Elderly patients are at increased risk of ADRs. Close to one out of every five elderly prescribed beta-lactams may develop ADR to the antimicrobial agent. Larger clinical studies are required to predict the risk factors of ADRs and poor responsiveness to antimicrobials.