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Using Administrative Claims to Identify Children With Chronic Conditions in a Statewide Immunization Registry | Page 3

Published Online: May 20, 2014
Kevin J. Dombkowski, DrPH, MS; Lauren Costello, MSW; Shiming Dong, MS; and Sarah J. Clark, MPH
Less than one-third of children received the seasonal influenza vaccine during either the 2008-2009 (29%) or 2009-2010 (32%) influenza seasons; 30% of children received the H1N1 vaccination in 2009-2010. The proportion of children with influenza vaccination or office visits during the 2008-2009 and 2009-2010 influenza seasons varied within health plans (Table 2). For both the seasonal and H1N1 vaccines, younger children were more likely to be vaccinated than older children; this was true for children enrolled in health plan 1 (P <.0001) and health plan 2 (P <.0001) across both influenza seasons. Vaccination rates did not differ by gender. For health plan 1, children residing in rural counties were more likely to receive the seasonal vaccination during both the 2008-2009 and 2009-2010 seasons (P <.0001) and H1N1 vaccination in the 2009-2010 season (P <.0001) compared with children from urban or unknown settings. Vaccination rates did not differ by county of residence for children enrolled in health plan 2.

Overall, 71% of all children were seen by a provider at least once in either season; nearly half had at least 2 provider visits in 2008-2009 (44%) and 2009-2010 (45%). Rates of office visits were highest among younger children across both influenza seasons and plans (P <.0001); adolescents (aged 11-18 years) were the least likely to be seen by a provider in both the 2008-2009 and 2009-2010 influenza seasons. Vaccination rates and office visits differed across health plans (Table 2). Compared with children enrolled in health plan 1, children enrolled in plan 2 had higher seasonal vaccination and office visits across both influenza seasons as well as H1N1 vaccination rates in the 2009-2010 season. Patterns among each plan remained consistent across influenza seasons.

Missed opportunities for influenza vaccination were commonplace among children each season and varied substantially across age groups (Figure 1). Among all children in our sample, 71% remained unvaccinated for influenza during the 2008-2009 season, 68% remained unvaccinated during the 2009-2010 season, and 70% remained unvaccinated for H1N1 in the 2009-2010 season. Among those who remained unvaccinated, nearly twothirds (63%) of children during both the 2008-2009 and 2009-2010 seasons had at least 1 missed opportunity for seasonal influenza vaccination; 50% of children had a H1N1 missed opportunity in 2009-2010. Children aged 6 to 18 months were most likely to have at least 1 missed opportunity for H1N1 vaccination (81%) and seasonal vaccination in the 2008-2009 (90%) and 2009-2010 (88%) seasons. The proportion of children with chronic conditions having a missed opportunity decreased sharply among older children. Given their lower numbers of office visits, adolescents had the lowest rate of missed opportunities for the seasonal influenza vaccine during 2008-2009 (58%) and 2009-2010 (57%) and the H1N1 vaccine during 2009-2010 (43%). Importantly, Figure 1 also illustrates the population that was unvaccinated for influenza and had no office visit; ranging from a minority of unvaccinated children 18 months or younger (≤10%) to nearly 50% of adolescents.

We estimated maximum vaccination rates potentially achievable if missed opportunities were successfully converted into administered influenza doses for children with chronic conditions enrolled in the commercial health plans (Figure 2). By converting initial missed opportunities into influenza vaccination events, cumulative gains of 45% (2008-2009) and 44% (2009-2010) were estimated for seasonal influenza vaccinations and 35% for H1N1 influenza vaccinations. If missed opportunities were eliminated, the commercially insured children with chronic conditions could potentially have experienced seasonal influenza vaccination rates that were markedly higher than the observed vaccination rates. If all missed opportunities were converted to vaccination events, seasonal vaccination rates in February would have been 74% versus 29% (2008-2009) and 75% versus 32% (2009-2010). H1N1 vaccination rates could have reached 65% by the end of the influenza season in 2010, versus the rate of 30% that was observed at that time.

Seasonal and H1N1 influenza rates for the 2008-2009 and 2009-2010 seasons as reported in MCIR only were contrasted between our cohort of children with chronic conditions identified by the commercial health plans with 2 matched groups of non–chronic condition children. Less than one-third of the enrollees with chronic conditions identified by the commercial plans received the seasonal influenza vaccine in either the 2008-2009 (26%) or 2009-2010 (29%) influenza seasons; 31% of children received the H1N1 vaccination in 2009-2010. In contrast, children enrolled in Medicaid without a chronic condition had sharply lower vaccination rates for seasonal (17% during 2008-2009 and 19% during 2009-2010) and H1N1 (18%) vaccinations. Similarly, children never enrolled in Medicaid without a chronic condition indication in the MCIR had comparably low seasonal vaccination rates during both seasons (16% in 2008-2009 and 18% in 2009- 2010), and 20% for H1N1.

DISCUSSION

Our findings demonstrate the feasibility of using administrative claims data from commercial health plans to identify children with chronic conditions and subsequently match them within a statewide immunization registry to enable a high risk indicator. This study extends previous findings that document accuracy in using Medicaid administrative data to identify children with chronic conditions in a statewide IIS.18 To our knowledge, this is one of only 2 studies that link billing-based identification data with statewide immunization registries17; however, previous studies have utilized similar approaches to identify chronic conditions from administrative data,18,20-22 including variations of the Healthcare Effectiveness Data and Information Set (HEDIS) methodology.23-26

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Issue: May 2014
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