WHO Disability Assessment Schedule 2.0: Responsiveness in Detecting Long-Term Functional Disability After Surgery

Anesthesiology Medicine
disability assessment postoperative function long-term responsiveness WHO assessment surgical recovery

With advances in anesthesia, surgery, and intensive care management, the short-term perioperative outcomes of surgical patients have significantly improved. However, an increasing number of studies are focusing on long-term outcomes directly related to patient prognosis, such as functional recovery or functional disability. Functional disability is defined as the difficulty patients encounter in performing basic daily living tasks or more complex tasks required for independent living. Although various scales (such as the Katz Activities of Daily Living Scale, Barthel Index, and Functional Independence Measure) have been developed to detect functional disability, these scales are typically only applicable to specific contexts (e.g., rehabilitation or orthopedic surgery). Therefore, the optimal tool for assessing postoperative functional disability remains debated.

The WHO Disability Assessment Schedule 2.0 (WHODAS 2.0) is a widely used scale for detecting postoperative functional disability, but its responsiveness within one year after surgery has been studied, while its long-term responsiveness (e.g., five years post-surgery) has not been sufficiently evaluated. Thus, this study aimed to assess the responsiveness of WHODAS 2.0 in detecting functional disability five years after surgery, filling this research gap.

Source of the Paper

This study was conducted by Yoko Yabuno, Yusuke Naito, Mitsuru Ida, and Masahiko Kawaguchi from the Department of Anesthesiology at Nara Medical University in Japan, along with Soshiro Ogata from the Department of Preventive Medicine and Epidemiology at the National Cerebral and Cardiovascular Center Research Institute. The paper was published in 2025 in the British Journal of Surgery (BJS), with the DOI 10.1093/bjs/znaf002.

Research Process

Study Participants and Design

This study is a secondary analysis of a prospective observational study. The participants were patients aged 55 or older who underwent elective non-cardiac surgery under general anesthesia. A total of 3,799 patients were enrolled, with 2,596 included in the final analysis. Patients completed the 12-item WHODAS and the Medical Outcome Study Short Form (SF-8) questionnaires before surgery and five years post-surgery.

Data Collection

Preoperative data collected included age, sex, body mass index (BMI), preoperative comorbidities (e.g., cerebrovascular disease, hypertension, ischemic heart disease), respiratory function, serum albumin and creatinine concentrations, and preoperative medication use (e.g., beta-blockers, steroids, statins). Surgical type and stress levels were assessed using the Operative Stress Score (OSS). Postoperative complications (e.g., reoperation, rehospitalization, stroke, myocardial infarction) were evaluated by researchers within one month after surgery.

Functional Assessment

Preoperative functional assessment was conducted through face-to-face interviews, while postoperative assessment was done via mail. Questionnaires were sent to patients at 3 months, 1 year, and 5 years post-surgery. If patients did not respond, researchers contacted them or their families by phone to obtain data. If no response was received after two phone calls, it was considered a non-response.

Responsiveness Evaluation

Responsiveness was evaluated using a three-step method:
1. Correlation Analysis: The Spearman rank correlation coefficient (ρ) was calculated between changes in WHODAS scores (ΔWHODAS) and changes in SF-8 physical scores (ΔPCS).
2. Subgroup Analysis: Patients were divided into improvement and decline groups based on ΔPCS and further subdivided into four subgroups. The median ΔWHODAS values of each subgroup were compared.
3. Standardized Response Mean (SRM) Calculation: The SRM was calculated for the overall cohort and subgroups predicted to have functional improvement or decline, and compared with the overall SRM.

Main Findings

Correlation Analysis

A moderate correlation was found between ΔWHODAS and ΔPCS (ρ = -0.47, 95% CI -0.50 to -0.44), indicating a significant relationship between changes in WHODAS scores and SF-8 physical scores.

Subgroup Analysis

In the subgroups with functional decline, the median ΔWHODAS values were 14.6, 6.25, 2.08, and 0, respectively. In the subgroups with functional improvement, the median ΔWHODAS values were 0, 0, -2.08, and -10.4, respectively. The differences between groups were statistically significant (p < 0.05).

Standardized Response Mean

The overall SRM was 0.18. The SRM for subgroups predicted to have functional improvement ranged from -0.45 to -0.67, while the SRM for subgroups predicted to have functional decline ranged from 0.17 to 0.56, indicating high responsiveness of WHODAS in detecting functional disability five years post-surgery.

Conclusion

WHODAS 2.0 demonstrates high responsiveness in detecting functional disability five years after surgery and can be used to assess long-term postoperative functional disability. This finding provides an important tool for the long-term care of postoperative patients.

Research Highlights

  1. Filling the Research Gap: This study is the first to evaluate the responsiveness of WHODAS 2.0 five years post-surgery, addressing a gap in long-term functional disability detection.
  2. Large Sample Size: The study included 2,596 patients, providing high statistical power.
  3. Multidimensional Assessment: Through correlation analysis, subgroup analysis, and SRM calculation, the study comprehensively evaluated the responsiveness of WHODAS.
  4. Clinical Application Value: The results support WHODAS 2.0 as a reliable tool for detecting long-term postoperative functional disability, offering significant clinical value.

Additional Valuable Information

The study also conducted sensitivity analysis by using a predictive model to impute missing data, further validating the robustness of the results. Although there was a certain dropout rate (31.3%), sensitivity analysis showed that dropouts did not significantly affect the study findings.

This study provides scientific evidence for the detection of long-term postoperative functional disability and offers important references for clinical practice.