Table 3.

Immediate cause of death and underlying conditions found in 326 RA death certificates by ICD-9 code

Condition (ICD-9 code range)	Total death certificates listing condition (%)a
Infectious & Parasitic Diseases (001 – 139)	55 (16.9 %)
Neoplasms (140 – 239)	69 (21.2 %)
Diseases of the Circulatory System (390 – 459)	172 (52.7 %)
Diseases of the Respiratory System (460 – 519)	123 (37.8 %)
Diseases of the Musculoskeletal Systemb (710 – 739)	68 (20.9 %)

^aPercentages add up to more than 100 % as many patients had more than one underlying condition across several ICD-9 code categories

^bTen patients have ICD-9 codes for Diseases of the Musculoskeletal System listed on the death certificate, but do not list RA