Evaluation of factors and patterns influencing the 30-day readmission rate at a tertiary-level hospital in a resource-constrained setting in Cape Town, South Africa

Abstract

Background: Factors contributing to and causes of hospital readmissions have been investigated worldwide, but very few studies have been performed in South Africa (SA) and none in the Western Cape Province.

Objectives: To investigate possible preventable and non-preventable factors contributing to readmissions to the Department of Internal Medicine at Tygerberg Hospital (TBH), Cape Town, within 30 days of hospital discharge. The researchers tested a risk-stratification tool (the LACE index) to evaluate the tool's performance in the TBH system.

Methods: A retrospective analysis was conducted of all 30-day readmissions (initial hospitalisation and rehospitalisation within 30 days) to the Department of Internal Medicine at TBH for the period 1 January 2014 - 31 March 2015. Potential risk factors leading to readmission were recorded.

Results: A total of 11 826 admissions were recorded. Of these patients, 1 242 were readmitted within 30 days, representing a readmission rate of 10.5%. The majority of patients (66%) were readmitted within 14 days after discharge. The most important risk factor for readmission was the number of comorbidities, assessed using the Charlston score. The study also identified a large burden of potentially avoidable causes (35% of readmissions) due to system-related issues, premature discharge being the most common. Other reasons for 30-day readmission were nosocomial infection, adverse drug reactions, especially warfarin toxicity, inadequate discharge planning and physician error.

Conclusions: Despite TBH being a low-resource, high-turnover system, the 30-day readmission rate was calculated at 10.5%. Global readmission rates vary from 10% to 25%, depending on the reference article/source used. We found that 35% of 30-day readmissions were potentially avoidable. Venous thromboembolism was a minor contributor to readmission but was associated with a very high mortality rate. A secondary outcome evaluated was the utility of the LACE and modified LACE (mLACE) index in the TBH environment. The risk tool performed well in the TBH population, and a high LACE and mLACE score correlated with an increased risk of 30-day readmission (p<0.001).