Measurement of polydoctoring as a crucial component of fragmentation of care among patients with multimorbidity: Cross-sectional study in Japan.

RVF was significantly correlated with FCI, polypharmacy, and higher outpatient medical costs. Unlike complex indices, RVF is simple and intuitively comprehensible. Further research is needed to evaluate the impact of care fragmentation on patient outcomes, considering factors such as RVF thresholds, patient multimorbidity, and social support. Understanding the influence of polydoctoring can enhance care quality and efficiency for patients with multimorbidity.