Journal Article

Multimorbidity is associated with uptake of influenza vaccination

Wei, Melissa Y., Lamerato, Lois E., Petrie, Joshua G., Harrison, Samantha M., Toth Martin, Emily

2018

Overview

•Multimorbidity is an improved measure of chronic disease among people at high risk for influenza.•Individuals with lower multimorbidity have lower influenza vaccination rates.•The MWI can more accurately describe influenza vaccine uptake than ACIP high-risk categorization. Patients with chronic conditions have higher rates of severe influenza-related illness and mortality. However, influenza vaccination coverage in high-risk populations continues to be suboptimal. We describe the association between cumulative disease morbidity, measured by a previously validated multimorbidity index, and influenza vaccination among community-dwelling adults. We obtained interview and medical record data for participants  ≥18 years who sought outpatient care for influenza-like illness between 2011 and 2016 as part of an outpatient-based study of influenza vaccine effectiveness. We defined cumulative disease morbidity by using medical diagnosis codes to calculate a multimorbidity-weighted index (MWI) for each participant. MWI and influenza vaccination status was evaluated by logistic regression. Akaike information criterion was calculated for all models. Overall, 1458 (48%) of participants out of a total of 3033 received influenza vaccination. The median MWI was 0.9 (IQR 0.00–3.5) and was higher among vaccinated participants (median 1.6 versus 0.0; p < 0.001). We found a positive linear association between MWI and vaccination, and vaccination percentages were compared between categories of MWI. Compared to patients with no multimorbidity (MWI = 0), odds of vaccination were 17% higher in the second category (MWI 0.01–1.50; [OR: 1.17, 95% CI: 0.92–1.50]), 58% higher in the third category (MWI 1.51–3.00; [OR: 1.58, 95% CI: 1.26–1.99]), 130% higher in the fourth category (MWI 3.01–6.00; [OR: 2.30, 95% CI: 1.78–2.98]) and 214% higher in the fifth category (MWI 6.01–45.00;[OR: 3.14, 95% CI: 2.41–4.10]). Participants defined as high-risk had 86% greater odds of being vaccinated than non-high-risk individuals (OR: 1.86, 95% CI: 1.56–2.21). The AIC was lowest for MWI compared with high-risk conditions. Our results suggest a dose response relationship between level of multimorbidity and likelihood of influenza vaccination. Compared with high-risk condition designations, MWI provided improved precision and a better model fit for the measurement of chronic disease and influenza vaccination.

• Publisher: Elsevier Ltd,Elsevier Limited
• Subject: Adult / Adults / Ambulatory Care / at-risk population / Chronic conditions / Chronic disease / chronic diseases / Chronic illnesses / Comorbidity / dose response / Female / Humans / Immunization / Independent Living / Influenza / influenza vaccination / influenza vaccines / Influenza Vaccines - administration & dosage / Influenza, Human - epidemiology / Influenza, Human - immunology / Influenza, Human - prevention & control / Influenza, Human - virology / Logistic Models / Male / Mathematical models / medical records / Michigan - epidemiology / Middle Aged / Models, Immunological / Morbidity / mortality / Multimorbidity / Odds Ratio / Patients / regression analysis / Risk / Socioeconomic factors / Vaccination / Vaccination - statistics & numerical data / Vaccine efficacy / Vaccines