Impact of patient characteristics on the risk of influenza/ILI-related complications.

Debra E Irwin,Lisa B Weatherby,Alexander M Walker,Daniel M Rosenberg,Suzanne F Cook,Wen-Yi Huang

doi:10.1186/1472-6963-1-8

Abstract

BackgroundWe sought to quantify the impact of patient characteristics on complications and health care costs associated with influenza and influenza-like illness (ILI) in a nonelderly population.MethodsPatients with medical reimbursement claims for influenza in the 1996–1997 season were identified from the automated database of a large private New England Insurer (NEI). Influenza care during the 21- day follow-up period was characterized according to age, gender, vaccine status, co-morbidities, prior influenza/ILI episodes, treatments, and recent health care costs and related diagnoses.ResultsThere were 6,241 patients. Approximately 20% had preexisting chronic lung disease. Overall, 23% had health care services for possible complications, among which respiratory diagnoses were the most common (13%). Two percent of the influenza/ILI episodes involved hospitalization, with a median stay of five days. Factors most strongly predictive of hospitalizations and complications were preexisting malignancy (hospitalizations OR = 3.7 and complications OR = 2.4), chronic heart disease (OR = 3.2 and OR = 1.8), diabetes (OR = 2.2 and OR = 1.7) and recent illnesses that would have counted as complications had they occurred during an influenza/ILI episode (hospitalizations OR = 3.2 and complications OR = 1.5). The same factors affected influenza-related costs and total costs of care as dramatically as they affected complication rates.ConclusionsInfluenza/ILI-related costs are driven by the characteristics that predict complications of influenza. Patients with chronic illness and those with recent acute respiratory events are the most likely to experience complications and hospitalizations.

Highlights

We sought to quantify the impact of patient characteristics on complications and health care costs associated with influenza and influenza-like illness (ILI) in a nonelderly population
The primary objective of this study was to examine the role of patient characteristics that might be predictive of complications and related health care costs associated with influenza and ILI
Up to five procedure codes are present on the claim records and are coded using ICD-9, Current Procedural Terminology (CPT), or Health Care Finance Administration (HCFA) codes. [8,9,10] Prescription drugs dispensed are identified by National Drug Code (NDC), American Hospital Formulary Service (AHFS) therapeutic category, brand name, and chemical name [11]

Summary

Introduction

We sought to quantify the impact of patient characteristics on complications and health care costs associated with influenza and influenza-like illness (ILI) in a nonelderly population. Influenza costs the US some 40,000 deaths, 200,000 hospitalizations, and millions of workdays lost each year. Little is known about influenza-related morbidity and health care costs in younger populations and among those with preexisting conditions such as diabetes, cardiovascular, or pulmonary disease. This study provides data on the burden to the health payor of influenza, ILI, and their related complications in a population of 2.6 million children and adults with various risk profiles.

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