Abstract

Background: Adverse Drug Reactions (ADRs) form one of the leading causes of morbidity and mortality particularly in the elderly population. Alterations in pharmacokinetics and pharmacodynamics with ageing results in increased ADRs which may be novel in respect to the young and may also vary from one older individual to another. These may hence be invaluable in personalized medicine.

Objective: The primary objective of this pilot study was to find the occurrence of ADRs in north Indian elderly patients admitted in the Geriatric ward, to analyze its epidemiological attributes and to draw conclusions regarding its implications in designing individualized treatment regimens and plan for larger multi-centric studies.

Methods: Elderly patients (>50 years age) admitted in the Geriatric ward were enrolled in this hospital-based, prospective observational study done during the period of September 2014 to September 2015 and June 2016 to October 2017. Adverse drug reaction data was collected based on self-reporting by patients or attendants and/or physician diagnosis.

Results: Out of 658 patients (M=388; F=270) admitted in the geriatric ward, 149 ADRs were reported in 103 patients (22.6%). 28 patients (4.2 % of all patients) experienced more than one ADR. Polypharmacy was seen in 98% cases of ADRs. Most commonly reported individual ADR was hypokalemia (13.4%) followed by diarrhea (8.7%). Electrolyte and metabolic abnormalities were the most common ADRs (27.5%) followed by the involvement of gastrointestinal system (18%) and central nervous system (13.4%). 120 (80.5%) ADRs were dose related i.e. Type A ADR and 22 ADRs (14.8%) were immunologic or type B ADRs. In addition, there were 2 cases of ADRs due to drug withdrawal (type E). Category wise, antibiotics were involved in maximum (32.2 % of ADRs) cases followed by diuretics (11.4 % of ADRs), intravenous fluids (10% of ADRs) and antihypertensives (9.4% of ADRs). The Naranjo scale was not applicable in 12.75% of ADRs; mostly due to multiple drugs or interactions being suspected. 55% ADRs were of moderate severity while 11% ADRs were of severe category. ADRs were found to increase the hospital stay by an average of 2 days. Mortality was seen in 4 cases with ADRs. 63% of ADRs were avoidable.

Conclusion: A higher than described incidence of ADRs was seen in our study. Polypharmacy was observed as a universal association. Antibiotics and diuretics were the common culprits. A greater fraction of ADRs is avoidable by proper vigilance and adequate monitoring. Awareness about the culprit drugs and associated regional variations may help in avoiding them in the older patients of specific ethnicities. The study highlights the incidence, severity and type of ADRs in the north Indian elderly population and gives platform for large-scale studies in future.

Keywords: Adverse drug reaction (ADR), elderly, geriatric, hospitalized, Naranjo, pharmacovigilance.

Graphical Abstract