A systematic review of patient adherence to medication instructions before elective surgery

Abstract Objective This systematic review aimed to evaluate the available evidence on patients’ adherence to medication instructions provided for their pre-existing medications before admission to hospital for their elective surgical procedure. Methods A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-registered systematic review was performed. A comprehensive literature search was conducted across five databases and two clinical trial registers. Studies involving patients (aged 18 years and over) undergoing elective surgery that reported quantitative data on adherence to pre-operative medication instructions before hospital admission were included. Methodological quality was assessed using the Mixed Methods Appraisal Tool. A narrative synthesis approach was used to report the findings. Key findings Eleven studies met the inclusion criteria, with overall methodological quality rated as moderate to high. Baseline adherence to pre-operative medication instructions before hospital admission ranged from 61.9% to 88.9% in studies reporting adherence without an evaluated intervention. Two studies reported statistically significant improvements in adherence with the implementation of a standardized medication instruction sheet. Factors influencing adherence included the format in which pre-operative medication instructions are provided (aOR = 1.83; P < 0.001), patient age (aOR = 0.67; P = 0.014) and (aOR = 2.1; P = 0.027), and literacy level (aOR = 1.9; 95% CI: 0.8–4.8). Conclusions Patients do not reliably follow the pre-operative medication instructions they are given before their hospital admission for elective surgery. The results emphasize the need for clear, standardized, multimodal medication instructions. Interpretation is limited by study heterogeneity, lack of randomization, and small patient numbers. Further research is warranted to explore the determinants of non-adherence and its potential impact on surgical cancellations and post-operative complications.