The Excess Hospitalization in Winter Versus Summer: Community-dwelling and Institutionalized Older Population in a Sub-tropical City

Abstract

<p>Background and Objectives: Excess hospitalizations were reported both in winter and summer, and winter used to have more hospitalizations than summer. Limited research investigated the trend of Excess Hospitalizations in Winter versus Summer (EHWS) in recent years. The differential trends among institutionalized and community-dwelling older adults remain underexplored. This study aimed to examine the pattern in EHWS among the community-dwelling and institutional older population in a sub-tropical city.</p><p>Methods: A retrospective study utilizing electronic medical records of population aged ≥65 from all public hospitals in 2012-2018 in Hong Kong was conducted. The EHWS Index was calculated based on the day-adjusted difference of inpatient admissions in winter (December, January, February) over summer (May, June, July) and divided by the inpatient admissions in winter. Corresponding 95% confidence interval (CI) was presented. The EHWS Index wasstratified by setting (community/institutional), sex and age.</p><p>Results: The EHWS Index of community-dwelling older people increased from 2012 (2.38%, 95%CI: 2.35%-2.41%) to 2014, then decreased till 2017 before a rise in 2018 (4.68%, 95%CI: 4.64%-4.72%). For institutional older people, the Index increased from 2012 (5.15%, 95%CI:5.05%-5.25%) to 2015 and decreased till 2017 before a rise in 2018 (7.60%, 95%CI:7.47%-7.74%). For both settings, the Index in 2017 was significantly less than 0. Generally, the Index increased with age in both men and women. </p><p>Conclusions: In 2017, which had the hottest August among the study period, the EHWS Indexin Hong Kong declined to a negative value, implying more inpatient admissions in summer than winter. Compared to community-dwelling older adults, institutional older adults had a larger Index, implying higher vulnerability to cold weather than hot weather. Enhanced care and environmental improvements during winter in nursing homes to alleviate the medical care burden is needed. </p>