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Updated: May 10, 2026

Inverse Probability of Treatment Weighting (Propensity Score) using the Military Health System Data Repository and National Death Index
Published on: January 8, 2020
Comparison of chronic disease prevalence between U.S. Navy ships without medical doctors and a similar shore-based
Edward S Hurd1, Paul D Rockswold, Richard J Westphal
1Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Building A, Room A1040-A, Bethesda, MD 20814, USA.
Objective:
Most U.S. Navy ships operate without embarked physicians, employing Independent Duty Corpsmen to provide primary and emergency medical care to crewmembers. We sought to characterize the burden of chronic disease faced by Independent Duty Corpsmen aboard Navy ships and compare it to that of a similar shore-based population.
Methods:
We conducted cross-sectional analyses of shipboard and shore-based samples using 1,305 records from Norfolk, Virginia-based U.S. Navy ships without doctors between March and May 2007, and records for Norfolk shore-based sailors from the same time frame matched 3:1 on age, sex, and race against the shipboard sample.
Results:
Asthma prevalence was 2.0% and 5.9% for the shipboard and shore-based samples, respectively (p < 0.0001). Cervical dysplasia among women was 16.2% and 23.1% (p = 0.3687). Depression was 4.6% and 8.4% (p < 0.0001). Diabetes was 1.0% and 2.3% (p = 0.0096). Hyperlipidemia was 20.6% and 21.4% (p = 0.5597). Hypertension was 25.5% and 36.1% (p < 0.0001). Total prevalence for any of the above conditions was 42.5% and 50.9% (p = 0.0001).
Conclusion:
Over 42% of shipboard sailors have one or more chronic health conditions. Even though the studied conditions were significantly less prevalent aboard ship than in the comparable shore-based sample, nonphysician practitioners aboard ships must be prepared to diagnose and treat chronic diseases.
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