Table 1.
Input Parameters for the Model
| Parameter | Point Estimate | Probability Distribution* | Source |
|---|---|---|---|
| Forecast of U.S. population growth and aging | — | — | U.S. National Population Projection (20, 21) (see online supplement) |
| Prevalence of asthma in United States across age, sex, and state | — | — | Global Burden of Disease studies (22, 23) (see online supplement) |
| Association between asthma control and age/sex† | Based on model calibration (see online supplement) | ||
| OR for well controlled (vs. very poorly controlled) | |||
| Age | 1.09 | Lognormal (0.08, 1.23) | — |
| Sex | 0.74 | Lognormal (−0.30, 1.32) | — |
| OR for not well controlled (vs. very poorly controlled) | |||
| Age | 0.99 | Lognormal (−0.01, 1.28) | — |
| Sex | 1.10 | Lognormal (0.09, 1.47) | — |
| Pooled OR of outpatient visit, uncontrolled (vs. well controlled) | 1.86 | Lognormal (0.62, 0.53) | Meta-analysis (see test and online supplement) |
| Pooled OR of emergency visit, uncontrolled (vs. well controlled) | 1.44 | Lognormal (0.36, 0.05) | Meta-analysis (see test and online supplement) |
| Pooled OR of hospitalization, uncontrolled (vs. well controlled) | 1.54 | Lognormal (0.43, 0.29) | Meta-analysis (see test and online supplement) |
| Pooled OR of medication use, uncontrolled (vs. well controlled) | 1.58 | Lognormal (0.45, 0.32) | Meta-analysis (see test and online supplement) |
| Average excess direct medical costs (per person-year),‡ uncontrolled (vs. well controlled) | 1,349 | Normal (1,349, 480) | Estimated through calibration, combining distribution of asthma controls and resource use ratios (above rows) with estimate of overall costs of asthma (3) |
| Pooled mean difference of average percentage of work time lost due to asthma, uncontrolled (vs. well controlled) | 12.70% | Lognormal (−2.06, 3.3) | Meta-analysis (see test and online supplement) |
| Average excess indirect medical costs (productivity loss, per person-year), uncontrolled (vs. well controlled) | 3,350 | Normal (3,350, 886) | Estimated through calibration, combining distribution of asthma controls and overall work impairment (above row) with estimate of average income (24) |
| Pooled mean difference of average QALYs lost due to asthma, uncontrolled (vs. well controlled) | 0.07 | Lognormal (−2.65, 0.01) | Meta-analysis (see test and online supplement) |
Definition of abbreviations: OR = odds ratio; QALY = quality-adjusted life year.
*
Normal (x, y): normal distribution with mean x and SD y; lognormal (x, y): lognormal distribution with mean x and SD y for the log-transformed values.
†
We modeled probability of three levels of control in the model but pooled “very poorly controlled” and “not well controlled” into “uncontrolled group” in order to report outcomes.
‡
All costs are in 2018 U.S. dollars.