Table 4.

—PH Studies Using ICD Codes

Study/Year Range	Database	Strategy	Select Reported Findings
Lilienfeld and Rubin7/1979-1996	NCHS	ICD-9 code 416.0	Mortality rates for IPAH increased in the United States from 1979-1996. Some portion of this increase may be related to anorexigens.
Rothman19/1990-1997	NCHS	ICD-9 code 416.0 limited to only age 20-54 y	Letter after Lilienfeld paper: There is no evidence of an epidemic around the peak years of fenfluramine use in the age groups most likely to have used anorexigens.
Movahed et al10/1990-2000	VA	ICD-9 code 416.0	Patients with diabetes mellitus have significantly higher prevalence of IPAH, independent of coronary artery disease, hypertension, congestive heart failure, or smoking (OR, 1.53; P < .05).
Hyduk et al8/1980-2002	Multiple	All PH codes combined	The number of deaths from PH (all forms) increased from 1980-2002, and older women represent the majority of decedents.
Peacock et al13/1986-2001	SMR	ICD-9 416.0 or ICD-10 I27.0 plus exclusion strategy	Prevalence of PAH may be higher than previously reported. This may be due to underestimation by the centers or overestimation by hospital data.
Davis et al11/1994-1998	NCHS	ICD-9 416.0	Blacks with PH exhibit a substantially increased mortality compared with whites, particularly black women.
Carrington et al14/1986-2001	SMR	Same as Peacock et al13	Mortality rates for PH are lower in the current era, particularly for patients with connective tissue disease-related PAH.

Six studies investigated trends or associations with IPAH (ICD-9 code 416.0), either using all IPAH diagnoses or using a strategy to identify patients more likely to truly have IPAH. One study evaluated all forms of PH combined (ICD-0 code 416.x) but did not look at the individual diagnosis codes. NCHS = National Center for Health Statistics Database; SMR = Scottish morbidity record; VA = Veterans Administration Hospitals. See Table 1 and 2 legends for expansion of other abbreviations.