Factors associated with early diagnosis of Developmental Dysplasia of the Hip in children: A population-based longitudinal study in Taiwan

Objective: In this population study of incidence of developmental dysplasia of the hip (DDH), we investigated disparities of early diagnosed in children at different socioeconomic and urbanization levels under Taiwan's National Health Insurance (NHI).

Methods: To identify the certain cases of DDH from NHI claims data, we used the following two inclusion criteria: (1) those with 3 or more ICD-9 codes (754.3 or 754.3X) in the outpatient claims file by orthopedic surgeons or those had DDH related surgeries. Logistic regression was used to examine the factors associated with early diagnosis of DDH.

Results: Approximately 2.13 million children were born from 1997 to 2004. Of these, 2,670 were diagnosed with DDH. The incidence rate from 1997 to 2004 ranged from 0.88 to 1.54 per thousand. The average of first diagnosed age is 1.01 years old. Around 80% of DDH patients were girls, 39% resided in rural area, 52% came from middle-class families, and more than 57% have never used free well-baby care before six months. Our multivariate analysis found that those who resided in urban area, came from higher socioeconomic families, and ever used free well-baby care before six months were more likely to be diagnosed earlier compared with rural, lower socioeconomic status and missing well-baby clinic.

Conclusion: Although Taiwan has provided universal insurance coverage; there was a disparity in timing of early diagnosis of DDH by urbanization level and socioeconomic status. The state-provided free well-baby care plays an important factor in early screening of DDH.