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Meta-Analysis
. 2022 Mar 1;5(3):e220740.
doi: 10.1001/jamanetworkopen.2022.0740.

Association of Body Mass Index With Clinical Outcomes in Patients With Cystic Fibrosis: A Systematic Review and Meta-analysis

Rita Nagy  1   2   3 , Noémi Gede  1 , Klementina Ocskay  1 , Bernadett-Miriam Dobai  1   4 , Alan Abada  1   5 , Zsófia Vereczkei  1 , Piroska Pázmány  1   3   6 , Dorottya Kató  1 , Péter Hegyi  1   2   7 , Andrea Párniczky  1   2   3
Affiliations
Meta-Analysis

Association of Body Mass Index With Clinical Outcomes in Patients With Cystic Fibrosis: A Systematic Review and Meta-analysis

Rita Nagy et al. JAMA Netw Open. .

Abstract

Importance: The prevalence of overweight (body mass index [BMI] = 25-29.9 [calculated as weight in kilograms divided by height in meters squared]) and obesity (BMI ≥30) is increasing among patients with cystic fibrosis (CF). However, it is unclear whether there is a benefit associated with increasing weight compared with the reference range (ie, normal) in CF.

Objective: To evaluate the association of altered BMI or body composition and clinical outcomes in patients with CF.

Data sources: For this systematic review and meta-analysis, the literature search was conducted November 2, 2020, of 3 databases: MEDLINE (via PubMed), Embase, and Cochrane Central Register of Controlled Trials.

Study selection: Patients older than 2 years diagnosed with CF with altered body composition or BMI were compared with patients having the measured parameters within the reference ranges. Records were selected by title, abstract, and full text; disagreements were resolved by consensus. Cohort studies and conference abstracts were eligible; articles with no original data and case reports were excluded.

Data extraction and synthesis: Two authors independently extracted data, which were validated by a third author. Studies containing insufficient poolable numerical data were included in the qualitative analysis. A random-effects model was applied in all analyses.

Main outcomes and measures: Pulmonary function, exocrine pancreatic insufficiency (PI), and CF-related diabetes (CFRD) were investigated as primary outcomes. Odds ratios (ORs) or weighted mean differences (WMDs) with 95% CIs were calculated. The hypothesis was formulated before data collection.

Results: Of 10 524 records identified, 61 met the selection criteria and were included in the qualitative analysis. Of these, 17 studies were included in the quantitative synthesis. Altogether, 9114 patients were included in the systematic review and meta-analysis. Overweight (WMD, -8.36%; 95% CI, -12.74% to -3.97%) and obesity (WMD, -12.06%; 95% CI, -23.91% to -0.22%) were associated with higher forced expiratory volume in the first second of expiration compared with normal weight. The odds for CFRD and PI were more likely in patients of normal weight (OR, 1.49; 95% CI, 1.10 to 2.00) than in those who were overweight (OR, 4.40; 95% CI, 3.00 to 6.45). High heterogeneity was shown in the analysis of pulmonary function (I2 = 46.7%-85.9%).

Conclusions and relevance: The findings of this systematic review and meta-analysis suggest that the currently recommended target BMI in patients with CF should be reconsidered. Studies with long-term follow-up are necessary to assess the possible adverse effects of higher BMI or higher fat mass in patients with CF.

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Conflict of interest statement

Conflict of Interest Disclosures: None reported.

Figures

Figure 1.
Figure 1.. Preferred Reporting Items for Systematic Reviews and Meta-analyses Flowchart
CENTRAL indicates Cochrane Central Register of Controlled Trials.
Figure 2.
Figure 2.. Pulmonary Function in Different Body Mass Index (BMI) Categories of Patients With Cystic Fibrosis
Comparison of patients with normal weight vs underweight (moderate heterogeneity detected) (A), normal weight vs overweight (substantial heterogeneity detected) (B), and normal weight vs obesity (considerable heterogeneity detected) (C). FEV1% indicates forced expiratory volume in the first second of expiration; WMD, weighted mean difference. The size of squares is proportional to the weight of each study. Horizontal lines indicate the 95% CI of each study; diamond, the pooled estimate with 95% CI.
Figure 3.
Figure 3.. Odds of Exocrine Pancreatic Insufficiency in Different Body Mass Index Categories
Comparison of patients with normal weight vs underweight (A), normal weight vs overweight (B), and normal weight vs obesity (C). OR indicates odds ratio. The size of squares is proportional to the weight of each study. Horizontal lines indicate the 95% CI of each study; diamond, the pooled estimate with 95% CI.
Figure 4.
Figure 4.. Odds for Cystic Fibrosis–Related Diabetes in Different Body Mass Index Categories
Comparison of patients with normal weight vs underweight (A) and normal weight vs overweight and obesity. OR indicates odds ratio. The size of squares is proportional to the weight of each study. Horizontal lines indicate the 95% CI of each study; diamond, the pooled estimate with 95% CI.
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