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| The Vermont Health Care Quality Report 2008 |
Ch2: Measuring Quality of Care Ch3: Chronic Illness in Vermont
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Healthcare Utilization in Vermont by Hospital Service Area and Various Population Characteristics (click for printable PDF) Introduction The following analyses were conducted to explore the relationship between several population characteristics and hospital discharge rates. The data sources used in these analyses included the hospital discharge data set, the Monograph Series, and the Vermont Household Health Insurance Survey. Combining these data sources allows one to look at hospital utilization rates in conjunction with several aspects about population served by local hospitals. All analyses are based on discharges from Vermont hospitals. If Vermont residents were hospitalized in an out of state hospital, those events are not captured in these analyses. As mentioned above, the analyses in this section of the Report are intended to explore relationships between hospital utilization and the populations that each hospital serves. Though these initial analyses are not conclusive and more in depth exploration of these relationships will be forthcoming, VPQ is including these preliminary analyses to promote discussion and hopefully lead to more insight as to the drivers of healthcare utilization in Vermont. How does the Health Status of a population influence Hospitalization? One possible factor influencing hospital discharge rates is the health of the population served by each hospital. The graph below illustrates the relationship between self-reported health status[1] (using the percent of population reporting that their health was “fair” or “poor”) and hospital discharge rates[2] in 2005. There is a statistically-significant (p<0.035)[3] positive relationship between the proportion of population reporting fair or poor health and the use of inpatient hospital care. That is, hospitals with higher discharge rates tend to have a higher percentage of Vermont residents living in that hospital’s service area who report being in poorer health. This finding emphasizes the need to adjust for the severity of illness when looking at hospital utilization data and making comparisons. Further exploration is needed to understand if there is any causal relationship.
Does the Prevalence of a Chronic Illness like Diabetes Influence Hospitalization?
Another approach to assessing the health of a population is by looking at chronic illness. The graph below illustrates the percent of people who have been told they have diabetes1 and hospital discharge rates2. The relationship between the hospital discharge rate and the percent of the population in the hospital’s service area that have been told they have diabetes is weak (p>0.1)3. Unlike a patient’s reported health status, the percentage of patients with diabetes does not appear to be associated with the use of inpatient services, though more in depth study with more robust data sets may show a relationship. Do Barriers to Access to Needed Care Increase Hospitalization? Another potential factor in use of inpatient care is the level of availability of other care. It has been theorized that barriers to appropriate primary care and other outpatient services may be associated with increased hospital use. This chart displays the relationship between hospital discharge rates2 and the percentage of the population in each HSA that reported an occasion in the last 12 months when they needed care from a doctor and did not get it because of cost1. The relationship between the hospital discharge rate and the percent of the population in the hospital’s service area that reported not getting the care they needed is weak (p>0.1)3. Unlike a patient’s reported health status, the percentage of patients that did not get the care they needed does not appear to be associated with the use of inpatient services.
Emergency Room Usage Some have suggested that higher usage of emergency departments is associated with higher use of inpatient care. As this chart illustrates, the relationship between the percentage of the population in each HSA that has used the ER in the last 12 months1 and each area’s inpatient discharge rate2 is not strongly associated (p> )3.
Insurance Status Lack of health insurance is frequently identified as a barrier to accessing needed healthcare. We might expect to see higher hospital inpatient usage in areas with higher uninsured rates because residents are not always getting timely care. There appears to be little if any relationship between the proportion of the population that is uninsured1 and the use of hospital inpatient care2.
Inpatient and Outpatient Over the last several years, there has been a substantial shift from inpatient to outpatient for many surgeries. Could some of the difference in inpatient use rates be related to the fact that they perform certain procedures on an outpatient basis? This analysis looks at seven different surgical procedures (knee arthroscopy, gall bladder surgery, treatment of broken legs excluding broken hip, hysterectomy, hernia repair, appendectomy, and mastectomy) that are fairly common and are frequently performed as both inpatient and outpatient. The percentage performed as inpatient procedures at each hospital is compared to the discharge rate in the area served by the hospital.
At first glance, there doesn’t not appear to be much of a relationship between discharge rates overall and the percentage of inpatient/outpatient procedures performed on an inpatient basis. However, additional analysis may be necessary to account for differences among hospitals in the care that they provide. Resources One of the most striking of Dr. Wennberg’s findings is that there is a strong association between the availability of healthcare uses and their use. For example, he has found that hospital discharge rates are frequently higher in areas where there are more hospital beds per person. This analysis examines whether this is true in Vermont. Because of the different roles played by critical access hospitals, tertiary hospitals, and large community hospitals, this chart identifies each hospital by type. Beds per 1,000 are calculated based on staffed beds (not licensed), including medical/surgical, pediatric, obstetric, ICU and psychiatric units. Long term care and nursery beds are excluded. The number of beds is divided by the service area population.
Fletcher Allen has the highest ratio of beds to population, but this is not surprising given its role as a referral hospital. Among the large community hospitals, there appears to be a weak positive association (areas with more beds / population have a slightly higher discharge rate). Among critical access hospitals, the relationship appears stronger, particularly for Springfield Hospital. [1] Vermont Household Health Insurance Survey [2] 2005 Vermont Hospital Monograph Series 3 p-value refers to the likelihood that the finding could happen by chance. When a finding is statistically significant there is a very small chance that it would happen just by chance.
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