Complications Associated with Underweight Primary Immunodeficiency Patients: Prevalence and Associations Within the USIDNET Registry

Abstract

Purpose: The point prevalence of underweight status and obesity in primary immunodeficiency disease (PID) is unknown, despite the described associations between PID and weight loss and failure to thrive. The goal of this study is to estimate the prevalence of underweight status and obesity in PID patients and to investigate the associations between abnormal body weight and complications of PID.

Methods: Using the US Immunodeficiency Network (USIDNET), we performed a retrospective analysis of 653 pediatric (age 2 to 20 years) and 514 adult (age > 20) patient records with information on patient body mass index (BMI). Prevalence of underweight and obese status in PID patients was compared to data from the National Health and Nutrition Examination Survey (NHANES).

Results: After separating BMI data by year of entry to the database, we demonstrated that both adult and pediatric patients with PID had significantly higher prevalence of underweight patients in multiple years of analysis. Further examination of underweight patients by PID diagnosis revealed that underweight status in adults with CVID was associated with granulomatous disease as well as earlier age of CVID diagnosis. In the pediatric CVID cohort, underweight status was significantly associated with lymphopenia. Examination of obesity in pediatric and adult PID patients compared to NHANES database revealed only a single year when obesity in PID patients was significantly less prevalent. In other 2-year time intervals from 2005 to 2014, the prevalence of obesity was unchanged in children and adults.

Conclusions: These results quantify the prevalence of underweight status in PID in a North American population and demonstrate that whether as a result of weight loss or poor weight gain, underweight status is more prevalent in the PID population than in the general US population. The prevalence of obesity in PID patients was similar to that seen in the general population. This highlights the need for continued education on the association of low weight and PID.

Clinical trial registration: NCT01953016.

Keywords: National Health and Nutrition Examination Survey (NHANES); Primary immunodeficiency; common variable immunodeficiency; failure to thrive; obesity; underweight.

Conflict of interest statement

Conflicts of Interest: none

All authors have no conflict of interest.

Figures

Figure 1:. BMI analysis by age, gender and immunodeficiency diagnosis.

A. Adult patients were grouped as a whole or by gender using standard BMI category definitions as shown in the figure legend. Data are presented as overall prevalence across all data entry years (percent ± 95%CI). B. BMI by PID diagnosis in adults, with median ± interquartile range displayed in red. BMI ranges are shaded on graph. White = normal range, lower dark gray range = underweight, light gray range = overweight, upper dark gray range = obese. C. Pediatric BMI percentile was calculated for each patient and used to determine underweight, overweight or obese status per CDC definitions as shown in the figure legend. Data are presented as overall prevalence across all data entry years (percent ± 95%CI). D. Breakdown of pediatric BMI in PID patients, by diagnosis. Median ± interquartile range displayed in red. Bottom dark gray shading = underweight (BMI percentile <5th), white = normal weight, light gray = overweight (BMI percentile 85th-95th) and top gray portion = obese (BMI percentile≥95th).

Figure 2:. Analysis of USIDNET data by year and comparison with National Health and Nutrition Examination Survey (NHANES) Data.

USIDNET patient data was categorized by year of visit and BMI category for comparison to NHANES [25,31] data for adults for A) obesity and B) underweight are represented as prevalence±95%CI. Pediatric USIDNET body weight status by two-year intervals compared to NHANES [24,26] data for C) obesity and D) underweight are also shown. (*p≤0.05)

Figure 3:. Underweight adults with CVID have earlier onset of symptoms and present earlier.

Adults with CVID were grouped by BMI into groups by body weight category. Physician-reported age of A) symptom onset (n=171) and B) age of diagnosis (n=260) are graphed individually and as mean±SEM. Between group differences were analyzed by linear regression with multiple comparisons with between group significance as noted.