Age-adjusted Baseline NDI Values: An Analysis of Neck Pain Disability in the General American Population.

ABSTRACT

STUDY DESIGN: Survey-based, prospective study. OBJECTIVE: Identify age-adjusted baseline NDI values in the American population. SUMMARY OF BACKGROUND DATA The Neck Disability Index (NDI) is the most widely used tool for assessing self-rated disability in patients with neck pain. Establishing baseline NDI values can aid in understanding the clinical impact of cervical spine pathologies and treatment interventions. METHODS: An internet-based survey was distributed using the Connect (TM) platform powered by CloudResearch. Based on the latest US Census, this survey was designed to engage a demographically representative sample of the US adult population. We captured 699 individuals, aiming for 100 people per each 10-year age group between 18-89. Participants scored their disability using the NDI survey. Mean NDI scores stratified by age group and sex were calculated for each cohort. RESULTS: A total of 699 participants were included with 352 (50.4%) males and 347 (49.6%) females and an age distribution closely aligning with national demographics. The overall mean NDI for the combined age groups was 16.5 with a 95% confidence interval (CI) of 15.5-17.5. The 18-29 age group had the lowest mean NDI of 12.3 (95% CI [10.4, 14.2]). Mean NDI scores increased until the 60-69 age group with a mean of 20.1 (95% CI [17.3, 23.0]) with women having a mean NDI of 22.2 (95% CI [18.8, 25.7]) compared to men with 15.4 (95% CI [10.3, 20.4]). Mean NDI scores decreased in the 70-79 and 80-89 age groups. CONCLUSION: This is the first study to assess age-adjusted baseline values of NDI in the US population. Our findings demonstrate a disproportionate distribution of disability ratings across age groups. This data is important for healthcare professionals as it provides age- and sex-specific levels of disability. LEVEL OF EVIDENCE Level III.