Factitious disorder and malingering in general hospitals in the United States: A retrospective analysis of the National Inpatient Sample 2017-2021.

OBJECTIVE

To examine socio-demographic characteristics, admission features, and comorbid diagnoses associated with hospitalizations assigned discharge codes for factitious disorder imposed on self (FDIS) and malingerer in United States acute care hospitals.

METHOD: This retrospective observational cohort study analyzed data from the 2017-2021 editions of the National Inpatient Sample, including adults (≥18 years) discharged with ICD-10-CM codes for FDIS (F68.1) or malingerer (Z76.5).

RESULTS

Across the five years, 15,620 acute care hospitalizations carried a discharge diagnosis of FDIS, compared with 215,005 for malingerer-an order of magnitude difference in frequency. FDIS hospitalizations showed a female predominance (65.6%) with mean age 42 years (SD 14), while malingerer was more often coded in men (56.3%). FDIS hospitalizations were associated with higher income quartiles and private insurance, whereas malingerer hospitalizations were associated with lower income quartiles, government-funded or no insurance, and more frequent discharge against medical advice. Both groups demonstrated high rates of psychiatric and general medical comorbidity, though substance use disorders were more common among malingerer hospitalizations. When specified, half of principal FDIS codes involved predominantly physical symptoms and 27.5% predominantly psychological symptoms.

CONCLUSION

Malingerer is coded more than ten times as often as FDIS in US inpatient medical care, and the two groups differ by sex, socioeconomic status, and comorbidities. These findings are best interpreted as descriptive of patterns in diagnostic coding, healthcare utilization, and associated morbidity, highlighting the importance of awareness of potential biases in labeling deceptive illness behavior given the implications for care, costs, and iatrogenic harm.