Reliability of patient-reported comorbidities: a systematic review and meta-analysis.

Self-reported questionnaires have become a widely adopted method of reviewing patients in clinical practice. This systematic review aimed to determine the reliability of patient-reported comorbidities and to identify which patient factors influence the reliability. Included studies assessed the reliability of at least one patient-reported comorbidity against their medical record or clinical assessment as gold standard. Twenty-four eligible studies were included in the meta-analysis. Only endocrine diseases (Cohen's Kappa Coefficient (CKC) 0.81 (95% CI 0.76 to 0.85)), consisting of diabetes mellitus (CKC 0.83 (95% CI 0.80 to 0.86)) and thyroid disease (CKC 0.68 (95% CI 0.50 to 0.86)), showed good-to-excellent reliability. Factors most frequently reported to influence concordance included age, sex and educational level. This systematic review demonstrated poor-to-moderate reliability for most systems, except for endocrine which showed good-to-excellent reliability. Although patient self-reporting can be a useful guide to clinical management, several patient factors were demonstrated to affect reliability therefore it should be avoided as a standalone measure.