Changes in rehabilitation service utilisation during COVID-19 bed surges in Japan: a seasonal autoregressive integrated moving average (SARIMA) analysis of care utilisation with 10-year claims data.

Inpatient rehabilitation services for cerebrovascular conditions showed a significant cumulative decrease associated with COVID-19 bed surges.

• The OE ratio of inpatient rehabilitation services for cerebrovascular conditions showed a significant decrease after five waves at -14.3%.
• The study used a SARIMA model to predict expected values, which were compared with actual values to calculate observed-to-expected (OE) ratios.
• Data covered acute care hospitals in Kanagawa Prefecture from April 2014 to March 2024.
• By March 2024, cerebrovascular rehabilitation showed only partial recovery.
• Patients aged 0-74 years enrolled in the National Health Insurance of Kanagawa Prefecture were included.

Musculoskeletal rehabilitation services declined during periods of high COVID-19 bed utilisation but demonstrated complete recovery by March 2024.

• Inpatient musculoskeletal rehabilitation showed declines similar to cerebrovascular rehabilitation during COVID-19 bed surge periods.
• By March 2024, musculoskeletal rehabilitation demonstrated complete recovery.
• The study covered multiple distinct COVID-19 pandemic waves and associated bed utilisation rate peaks.
• OE ratios were calculated for both volume of rehabilitation services provided and number of patients per insured person.

Respiratory rehabilitation displayed a unique pattern, with inpatient services increasing substantially above expected levels early in the pandemic before sharply declining.

• Inpatient respiratory rehabilitation services increased up to 62.4% above expected levels until September 2021.
• After September 2021, inpatient respiratory rehabilitation sharply declined.
• Respiratory rehabilitation exhibited mixed patterns overall, with persistent outpatient deficits remaining by March 2024.
• This pattern was distinct from the predominantly negative impacts seen in cerebrovascular and musculoskeletal rehabilitation.

Outpatient rehabilitation services experienced sharp initial declines but showed differential recovery patterns across rehabilitation types.

• Outpatient services experienced sharp declines initially during the COVID-19 pandemic.
• Recovery patterns differed across cerebrovascular, musculoskeletal, and respiratory rehabilitation types.
• Respiratory rehabilitation exhibited persistent outpatient deficits through March 2024.
• Some structural changes in outpatient rehabilitation persisted beyond the acute pandemic phase.

The study used a seasonal autoregressive integrated moving average (SARIMA) model applied to 10 years of insurance claims data to estimate expected rehabilitation utilisation.

• The retrospective study used a SARIMA model to predict expected values of rehabilitation service utilisation.
• Data spanned April 2014 to March 2024, providing a pre-COVID baseline and pandemic-era comparison.
• The study population was patients aged 0-74 years enrolled in the National Health Insurance of Kanagawa Prefecture.
• Kanagawa Prefecture was selected as it has the second largest population in Japan after Tokyo.
• Outcomes included volume of rehabilitation services provided and number of patients per insured person, expressed as OE ratios.

The findings indicate that inpatient rehabilitation for cerebrovascular and musculoskeletal conditions was particularly vulnerable to disruption during high COVID-19 bed utilisation periods.

• Inpatient services for cerebrovascular and musculoskeletal conditions were identified as 'particularly vulnerable to disruptions during high COVID-19 bed utilisation periods.'
• Multiple distinct peaks in COVID-19 bed utilisation were associated with repeated declines in these rehabilitation services.
• The differential recovery patterns across rehabilitation types indicate structural changes persisting beyond the acute pandemic phase.
• The authors conclude there is 'need for flexible healthcare systems to deal with future healthcare crises.'