Swallowing function and the incidence of fever in older residents with special care needs: a one-year longitudinal prospective study

Abstract Background Infectious diseases including aspiration pneumonia are the most frequent causes of fever, common in older residents of nursing homes. We investigated whether swallowing dysfunction was related to fever in such residents. Methods Older residents aged ≥ 65 years from three nursing homes were included in this prospective study conducted from July 2017 to May 2019. The follow-up period was 13 months. The outcome was fever incidence in relation to swallowing function. Baseline data on the activities of daily living, cognitive function, swallowing function, respiratory function, tongue pressure, and comorbidity conditions were collected. Dates on which the body temperature of participants was more than 37.5 °C during the follow-up period were also recorded. For statistical analysis, swallowing function assessed by the modified water swallow test (MWST) scores were used to divide the participants into three groups; scores ≤ 3, 4, and 5. Results A total of 52 participants [median age, 89.5 (67–104)] were enrolled. Kaplan-Meier analysis showed that the average periods until onset of fever in participants with MWST scores of ≤ 3, 4, and 5 were 8.0 (6.0–11.0), 10.0 (7.0–12.0), and 12.0 (10.0–13.0) months, respectively. Cox’s proportional hazards regression model revealed that participants with an MWST score ≤ 3 were at a higher risk of fever compared to those with an MWST score of 5 (hazards ratio 13.0, 95% confidence interval 1.9–87.6), adjusted with possible confounders. Conclusions Swallowing dysfunction correlated with the risk of fever in older residents of nursing homes.