Validation of intellectual disability coding through hospital morbidity records using an intellectual disability...

Area of Science:

• Public Health
• Epidemiology
• Disability Studies

Background:

• Accurate ascertainment of intellectual disability (ID) is crucial for epidemiological research and service planning.
• Hospital morbidity data systems are often used for health surveillance but their utility for specific conditions like ID requires validation.

Purpose of the Study:

• To evaluate the effectiveness of the Western Australian Hospital Morbidity Data System (HMDS) in identifying individuals with intellectual disability (ID) compared to a dedicated population-based database.

Main Methods:

• A cohort of children born between 1983-2010 with hospital admissions in HMDS was linked with the Western Australian Intellectual Disability Exploring Answers (IDEA) database.
• International Classification of Diseases (ICD) codes indicative of ID were identified within HMDS.

Main Results:

• Out of 488,905 individuals, 10,218 had ID. Only 14.7% of ID cases were identified through HMDS, with 4.7% unique to HMDS.
• Cases unique to HMDS were often deceased infants, and those identified in HMDS were more likely to be younger, female, non-Aboriginal, and have severe ID.
• HMDS demonstrated high specificity (99.9%) but low sensitivity (14.7%) for ID ascertainment.

Conclusions:

• Hospital morbidity data alone is not a reliable source for identifying intellectual disability in population-based studies.
• Epidemiological researchers must consider the limitations of hospital data and utilize more comprehensive sources for accurate ID ascertainment.