ABSTRACT
<p><b>INTRODUCTION</b>The objective of this study was to determine factors, other than the Diagnostic Related Grouping (DRG), that can explain the variation in the cost of hospitalisation and length of hospital stay (LOS) in older patients.</p><p><b>MATERIALS AND METHODS</b>This was a prospective, observational cohort study involving 397 patients, aged 65 years and above. Data collected include demographic information, admission functional and cognitive status, overall illness severity score, number of referral to therapists, referral to medical social worker, cost of hospitalisation, actual LOS, discharge DRG codes and their corresponding trimmed average length of stay (ALOS).</p><p><b>RESULTS</b>The mean age of the cohort was 80.2 years. The DRG's trimmed ALOS alone explained 21% of the variation in the cost of hospitalisation and actual LOS. Incorporation of an illness severity score, number of referral to therapists and referral to medical social worker into the trimmed ALOS explained 30% and 31% of the variation in the cost and actual LOS, respectively.</p><p><b>CONCLUSION</b>The DRG model is able to explain 21% of the variation in the cost of hospitalisation and actual LOS in older patients. Other factors that determined the variation in the cost of hospitalisation and LOS include the degree of illness severity, the number of referral to therapists and referral to medical social worker.</p>