Asthma in Families Facing Out-of-pocket Requirements With Deductibles
Condition: Asthma
MeSH terms: Asthma
Study type: Observational

Summary: 
      Asthma is one of the most common chronic diseases in the U.S. Despite guidelines, adherence
      to recommended controller medications is low. Cost is an important barrier to adherence.
      Employers are increasingly adopting high-deductible health plans (HDHPs) which require
      deductibles of > $1,000 per individual/$2,000 per family each year. In HDHPs with Health
      Savings Accounts (HSAs), most medications and non-preventive care must be paid out-of-pocket
      (OOP) until the deductible is reached. The lower premiums of HSA-HDHPs are appealing, but the
      high level of OOP costs can lead patients to forgo needed care. HSA-HDHPs can exempt
      preventive care from the deductible, and employers can add Preventive Drug Lists (PDLs) which
      exempt certain chronic medications from the deductible (including asthma medications), making
      them free. PDLs have the potential to improve controller medication use, which could prevent
      negative health outcomes and reduce cost-related trade-offs for families.

      The goal of this research is to evaluate the impact of these two developments in the health
      insurance market -- HSA-HDHPs and PDLs -- on medication use and clinical outcomes for adults
      and children with asthma. To do this, tteh investigators will first conduct in-depth
      interviews with patients with asthma and parents of children with asthma who have HDHPs and
      traditional plans. Interviews will collect patient-reported data on how patients and their
      families navigate their insurance plan and make health care decisions when faced with OOP
      costs. Findings from the interviews will inform analyses of data from a large national health
      plan from 2004-2017. Investigators will select adults and children with asthma whose employer
      switched them from traditional plans or HSA-HDHPs without PDLs to HSA-HDHPs with or without a
      PDL. Analyses will examine changes in asthma medication use, emergency department (ED)
      visits, hospitalizations, and OOP costs before and after changing plans compared to similar
      patients who did not switch to a HSA-HDHP. The study aims to: 1) understand health care
      decision making and experiences of families with asthma with HDHPs; 2) examine the impact of
      HSA-HDHPs with and without PDLs on use of asthma medications and asthma-related ED visits and
      hospitalizations; 3) examine the extent to which the response to HSA-HDHPs and PDLs is
      affected by the presence of other family members with asthma or other chronic conditions; 4)
      examine the impact of HSA-HDHPs with and without PDLs on OOP costs for families.
    

Detailed description: 
      Background and Significance Asthma is one of the most common serious chronic diseases of
      adults and children in the United States. Despite guidelines and evidence, adherence to
      recommended asthma controller medications is low. Cost is an important barrier to
      non-adherence to asthma medications. Employers are increasingly adopting high-deductible
      health plans (HDHPs) particularly those that qualify for Health Savings Accounts (HSAs),
      which subject most medications to deductibles rather than copayments as in traditional
      coverage. HSA-HDHPs can thus lead to forgone care due to cost, including clinically
      appropriate services such as asthma medications. As a response, value-based insurance designs
      (VBID) have been proposed to promote high-value care by reducing or eliminating cost-sharing
      for these services. One common example is a Preventive Drug List (PDL) that can accompany
      HSA-HDHPs, which exempts certain chronic medications from the deductible to promote
      adherence. Many PDLs include asthma controller and rescue medications. With the increasing
      prevalence of HSA-HDHPs, PDLs have the potential to improve controller medication adherence
      for both adults and children.

      Study Aims: The goal of this research is to provide needed evidence on the impact of two
      important developments in the health insurance landscape, HSA-HDHPs and PDLs, and whether
      PDLs can mitigate cost barriers associated with HSA-HDHPs and improve patient-centered
      outcomes for adults and children with asthma. The Aims of this research are:

        1. To understand health care decision making and experiences of families with asthma with
           HSA-HDHPs and PDLs.

        2. To examine the impact of HSA-HDHPs with and without PDLs on use of asthma controller and
           rescue medications, and on adverse clinical outcomes (asthma-related ED visits and
           hospitalizations), overall and for vulnerable subgroups (low-income and racial/ethnic
           minority patients).

        3. To examine the extent to which the response to HSA-HDHPs and PDLs is affected by the
           presence of other family members with asthma or other chronic conditions.

        4. To examine the impact of HSA-HDHPs with and without PDLs on OOP costs for patients and
           families with asthma.

      Sources of Data

      Aim 1. This study will collect patient-reported data through in-depth qualitative phone
      interviews

      Aims 2-4 will use 14 years (2004-2017) of enrollment and claims data from a large U.S.
      commercial health plan

      Study Population

      The Aim 1 study population will consist of adults with asthma and parents of children with
      asthma. Eligible participants will be those who are currently enrolled in employer-sponsored
      health insurance plans (high-deductible plans with and without a PDL, or traditional plans).

      The health plan population will be identified through enrollment and claims data from Harvard
      Pilgrim Health Care (HPHC). Eligible patients will include adults aged 18-64 and children
      aged 4-17 years with a diagnosis of asthma. Patients will be selected if they have been
      enrolled in an employer-sponsored HSA-HDHP with or without a PDL, or a traditional plan
      without a high deductible, for the prior year. Among those eligible in each sub-group, the
      investigators will randomly select 9 from each cell to send a recruitment mailing, for a
      total of 81 patients or parents invited to participate.

      A population from the Asthma and Allergy Foundation of America (AAFA) will be recruited
      through postings to AAFA's Asthma Online Community, Educational Support Group, email list
      serve, Facebook page, and newsletters.

      For Aims 2-4, the study population will consist of adults aged 18-64 years and children aged
      4-17 years with asthma. Study subjects must have spent a year in a traditional health plan
      with no or low deductibles prior to the switch to an HSA-HDHP without a PDL, or in a HSA-HDHP
      without a PDL prior to switching to an HSA-HDHP with PDL, and then remain enrolled for at
      least one year post-switch. Control group members spend a year in a traditional plan or HDHP
      without PDL then remain in that plan for at least another 12 months.

      Enrollees over age 64 who are eligible for Medicare will be excluded. The investigators will
      identify members with asthma during the baseline year using the same claims-based algorithm
      in which an asthma diagnosis will be defined as having at least one inpatient or two
      outpatient claims in the prior year with a diagnosis of asthma based on International
      Classification of Diseases (ICD) 9 and 10 codes for asthma.

      Eligible employers are those that offer only one plan type in a given benefit year: 1)
      traditional Health Maintenance Organization/Preferred Provider Organization/Point of Service
      plans (deductibles <$1000, copayments of <$50 for most services, tiered copayments for
      medicines); 2) HSA-HDHPs without PDLs; or 3) HSA-HDHPs with PDLs. The investigators will
      select "full-replacement" employers that replace a traditional plan or HSA-HDHP without PDL
      with an HSA-HDHP without PDL or HSA-HDHP with PDL, respectively, for all employees at a given
      point in time; matched comparison employers will include those that keep all employees in
      their prior plan.

      Outcomes

      Aim 1 qualitative interviews will assess patient and family experiences across a number of
      domains related to asthma health care decision making and outcomes in HDHPs.

      The primary study outcomes for Aims 2-4 are the claims-based measures of asthma medication
      use, outcomes, and OOP costs listed below, measured at the individual level. See section on
      primary outcomes for details,

      Predictors and Covariates

      The primary predictor variables include study period and insurance type. Study period
      indicates the one-year period before or up to three years after the index date. Insurance
      type includes: 1) HSA-HDHP without PDL; 2), HSA-HDHP with PDL; and 3) traditional plan.

      Other co-variates include baseline asthma severity, co-morbidity, presence of other chronic
      conditions, self-reported and geocoded race/ethnicity data, neighborhood education and
      poverty levels, sex, age, state, individual versus family plan, baseline number of outpatient
      visits, presence of an inpatient hospitalization, total expenditures, employer size, average
      employer baseline expenditures per capita, number of family members, mean age of children in
      the family, mean age of adults, baseline mean family morbidity score, number of family
      members with asthma, number of asthma and other medications used by the family, and number of
      family ED visits and hospitalizations in the baseline year.

      Analysis plan

      Aim 1

      The study team will analyze qualitative data in iterative cycles of content analysis in the
      manner described by Patton. In the second, deductive phase of analysis, investigators will
      consider data code-by-code to identify areas of convergence and divergence by insurance type.

      Aim 2

      Analyses will compare changes in outcomes from baseline to up to three years of follow-up
      among 1) asthma patients switched to HSA-HDHPs without PDLs from traditional plans vs.
      matched patients whose employers remain in traditional plans; and 2) patients switched to
      HSA-HDHPs with PDLs from HSA-HDHPs without PDLs vs. matched controls remaining in HSA-HDHPs
      without PDLs. The investigators will use separate regression models to compare year-to-year
      changes for each intervention group relative to its matched control group, rather than
      including all patients in a single model with multiple interaction terms.

      The analyses will use both Interrupted Time Series (ITS) and Difference-in-Differences (DiD)
      frameworks. Controlling for potential confounders, analyses will use generalized linear
      models (GLMs) to model the independent effect of switching to each of the two types of
      HSA-HDHPs (with or without PDLs) on the likelihood of each outcome, assessed by interacting
      insurance type and study period variables in models. Extended GLMs - generalized estimating
      equations (GEE) and generalized linear mixed models (GLMM) - are appropriate methods to
      adjust for correlation within families and to examine changes in outcomes between baseline
      and follow-up.

      This study will examine controller medication adherence using ITS. Investigators will test
      the statistical significance of level or trend changes following insurance plan type switch
      using GLM models, adjusting for seasonality and first-order autocorrelation between
      sequential monthly measurements using the empirical sandwich estimator.

      For analyses of rescue medication use, investigators will focus on albuterol and levalbuterol
      inhaler users. The standardized number of rescue inhalers dispensed will be modeled as count
      data in difference-in-differences models. ITS models will be used to model changes in level
      and trend of monthly rates of rescue inhalers dispensed, as in previous studies. Analyses
      will also model the ratio of controller medications to total asthma medications. For analyses
      of asthma-related ED visits and hospitalizations, outcomes can be binary, counts, or
      continuous. The investigators will use logistic GEE models to estimate the effect of
      switching to each type of HSA-HDHP on binary outcomes such as any asthma-related
      hospitalization. Negative binomial regression will be used to model the effect for count
      outcomes such as ED visits. Investigators will select the conditional mean and variance
      functions based on the actual data, using a log link with a Gamma error distribution.

      To determine the impact of HSA-HDHP with and without PDLs on vulnerable populations and test
      for heterogeneity of treatment effects among vulnerable populations, the investigators will
      first perform stratified analyses, comparing outcomes between intervention and control
      subgroups defined by the binary measures of the risk factors of interest (low income,
      minority race/ethnicity, moderate-severe asthma, presence of other chronic conditions, high
      morbidity based on the Johns Hopkins Adjusted Clinical Groups (ACG) system). Analyses will
      use three-way interaction terms (insurance type * study period * subgroup) to test for
      statistical differences between subgroups in the impact of the change to an HSA-HDHP with PDL
      vs. remaining in a traditional plan. In Aim 2 analyses, the investigators will include both
      adults and children together, with age included as a co-variate.

      Aim 3

      Analyses will use the same population, outcomes, study group comparisons, and modeling
      strategies as Aims 1 and 2 except that stratified analyses will be performed, comparing
      outcomes between intervention and control groups stratified by adult/child status. To
      statistically test for heterogeneity of treatment effect for adults vs. children, analyses
      will use three-way interaction terms (insurance type * study period * adult/child) to test
      for statistical differences between adults and children in the impact of the change to an
      HSA-HDHP with PDL vs. remaining in a HSA-HDHP without PDL. Analyses will be done at the
      individual level, but will include family-level variables as predictors of interest.
      Separately for adults and children, the investigators will test the extent to which having
      another family member with asthma, another chronic condition, or high baseline family ACG
      morbidity modifies the impact of HDHPs and PDLs on study outcomes for an individual asthma
      patient. The primary predictor of interest will be the interaction between the family-level
      variable, study period, and study group.

      Aim 4

      Analyses will be similar to those of Aim 2, but for OOP cost outcomes. The primary analyses
      of changes in OOP costs will use a DiD analytic framework. The investigators will follow the
      same approaches as used in analyzing ED visits and hospitalizations, employing two-part
      models/zero-inflated negative binomial models to account for zero costs. GEE or GLMM models
      will be used to examine changes in outcomes between baseline and follow-up to model the
      independent effect of switching to each of the two types of HSA-HDHPs (with or without PDLs)
      on the likelihood of having financial burden (OOP cost greater than 5% of income).
    

Intervention name(s): HDHP with PDL
Intervention type(s): Other
Intervention description(s): Enrollment in a Health Savings Account-eligible high-deductible health plan with an annual individual deductible of >$1000 that includes a preventive drug list (a list of certain chronic medications that are exempt from the deductible)
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        Adults and children with asthma enrolled in an employer-sponsored plan from a large
        national insurance carrier between 2004 - 2017.
      
Keywords: high-deductible health plan; medication adherence; out-of-pocket costs; preventive drug list; value-based insurance design