From a health-care insurance perspective, it cost 585€ to deliver education including the IEP; 461€ was saved in health expenses. Adjusting for benefits in the control group, 0.79€ was saved for every 1.00€ spent in the first year after intervention.
Adding the IEP to the SPMP yields incremental morbidity cost savings of 160€ (direct costs) at an additional average cost of 44€ when compared to the SPMP alone. This translates into a benefit-cost ratio of 3.65.
Lung function as measured with PEF increased significantly (p > 0.05) in all study groups. FEV1 did not change significantly over time in any of the three groups. Changes in lung function are shown in Table 7. Subgroup analysis of the main study outcome shows higher benefit-cost ratios for patients with moderate persistent or severe persistent asthma (1.42 in the IEP group) and for patients with any emergency 6 months prior to the study entry (1.21 in the IEP group) [Table 6]. this
In the framework of one-way sensitivity analysis, several cost items and assumptions have been modified in order to test for their impact on the benefit-cost ratio (Table 8). The ratio is most sensitive to changes in the drug adherence. Assuming a constant reduction in morbidity cost savings in the year following the observational period, ie, allocating just 50% of the educational costs to the observational period, the benefit-cost ratio becomes > 1 for the IEP group while getting close to 1 for patients within the SPMP group. The benefit-cost ratio is more robust to elevations of GP fees and the IEP reimbursement level.
QoL as indicated by the KINDL total QoL score increased significantly (p < 0.05) in both intervention groups. QoL decreased to a little but nonsignificant extent in the CG. Statistically significant (p < 0.05) improvements were observed in four domains of the KINDL questionnaire among patients using the IEP and in three domains among patients receiving the SPMP (Fig 3). Statistically significant improvements (p < 0.05) were also observed in the asthma-specific module in both intervention groups.
Table 7—Results of Lung Function Tests
|No.||Mean ± SD, L/min||INo.||Mean ± SD, L/min|
|SPMP plus IEP|
|Baseline||42||340 ± 86*||35||99.2 ± 12.2t|
|Visit 1||33||363 ± 89*||16||96.3 ± 14.0|
|Visit 2||32||368 ± 92*||14||89.6 ± 11.4|
|Baseline||46||324 ± 98||38||90.8 ± 14.5|
|Visit 1||41||341 ± 110*||32||93.4 ± 11.2|
|Baseline||70||347 ± 94||69||
|Visit 1||63||366 ± 101*||29||98.4 ± 18.9|
|Visit 2||49||376 ± 97*||25||98.1 ± 15.7|
Table 8—Calculation of Adjusted Costs
|Variables||SPMP Group Plus IEP Group,No. (%)||SPMP Group,No. (%)||Direct Costs Group A, €||Formula for Calculating Weighted Costs||Result Weighted Cost, €|
|Intermittent||3 (7)||12 (14)||455||455 X 0.14/0.07/44||21|
|Mild persistent||12 (27)||36 (42)||519||519 X 0.42/0.27/44||18|
|Moderate persistent||27 (61)||37 (43)||582||582 X 0.61/0.43/44||18|
|Severe persistent||2 (5)||1(1)||1,351||1,351 X 0.01/0.05/44||270|
|Total||44 (100)||86 (100)||327|
Figure 3. Changes in QoL as measured with the KINDL questionnaire. Results are presented by domains and as a total score for baseline and follow-up visits. See Figure 2 legend for expansion of abbreviations.