Prevalence and impact of abnormal routine pre-operative test results among elective surgical patients with or without co-morbidity: An observational comparative study

Background: At present, selective and clinical assessment-based pre-operative investigations are advocated, but it is yet far from routine practice. Aim: This study aims to assess the prevalence and impact of abnormal routine pre-operative test results among co-morbid and non-co-morbid elective surgical patients. Methods: Data for this prospective study were collected by reviewing the medical charts of the patients attending pre-anaesthetic clinic from December 2016 to April 2017. The cohort was divided into non-co-morbid and co-morbid. Routine pre-operative tests were done, their results and impacts of abnormal test results were noted; number needed to investigate (NNI) was calculated. Data were compared using Fisher's exact test, unpaired t-test, etc., P < 0.05 was considered statistically significant. Results: Data from 887 patients; 322 (36.30%) co-morbid were analysed. Co-morbid patients were older (53.79 ± 14.99 vs. 40.33 ± 15.68 year). No difference was found in the number of tests done in co-morbid patients except significantly higher number of electrocardiogram and echocardiography (P < 0.0001). Abnormal test results were significantly higher among co-morbid (relative risk - 1.63, P < 0.0001). Impacts were similar in co-morbid as compared to non-co-morbid for most of the tests, but thyroid function and blood sugar tests showed NNI for significant impact below 10 in co-morbid group. Conclusion: Co-morbid patients have more abnormal results than non-co-morbid patients, but impacts of such tests are nearly indifferent. Routine testing is not favourable even in co-morbid patients. Selective or co-morbid disease-specific tests are having more significant impacts and should replace the 'routine testing' even in co-morbid patients.