The Prevalence of Immunocompromised Adults: United States, 2013

Background: The number of immunocompromised (IC) adults in the US is likely increasing due to new indications for immunosuppressive treatments and to improvements in medical management and life-expectancy of these adults. Such increases can have major public health implications due to risks from reactivation of chronic infections (e.g. tuberculosis, toxoplasma, zoster) and from exposure to opportunistic infections (e.g. listeria, cryptosporidium). Yet comprehensive data on prevalence of all-cause IC have never been published. We report data on prevalence of self-reported IC adults in the U.S.

Methods: We conducted a cross-sectional analysis of US adults aged 18 years and older using the 2013 National Health Interview Survey (NHIS). Respondents were asked if they had ever been told by a health professional that their immune system was weakened and if that status still pertained. Follow-up questions were used to assess the cause of IC and to better assure the validity of the self-reported results; in sensitivity analyses we varied criteria for IC. We generated national estimates of prevalence of IC, taking into account the complex NHIS sampling design.

Results: Of 34,426 respondents, 4.2% (1,442) had been told at some time by a health professional that they were IC. Of these, 2.8% (n=951) reported they were currently IC, translating to a prevalence of 2.7 (2.4, 2.9). In sensitivity analyses, prevalence ranged from 1.8% (95% CI: 1.6, 2.0) to 3.1% (95% CI: 2.9, 3.3). Data on IC prevalence among different demographic strata appear in the Table:

Characteristic	No. (%)	Prevalence per 100 US population (95% CI)
Self-report of current immunocompromise	951 (2.8)	2.7 (2.4, 2.9)
Sex
Male	298 (31.3)	1.8 (1.5, 2.1)
Female	653 (68.7)	3.5 (3.1, 3.9)
Age Group (years)
18-39	182 (19.1)	1.6 (1.3, 1.9)
40-49	136 (14.3)	2.3 (1.8, 2.8)
50-59	281 (29.5)	4.4 (3.7, 5.1)
60-69	213 (22.4)	3.9 (3.2, 4.5)
70-79	101 (10.6)	3.1 (2.4, 3.8)
80+	38 (4.0)	2.5 (1.4, 3.5)

 

Conclusion: The number of IC adults in the US may be increasing with important implications yet the prevalence of this phenomenon has not previously been reported. Our data are self-reported but our questions designed for validity. These data can be important for planning purposes and to provide a baseline with which to assess trends.