Studies performing health-economic evaluations of iCBT interventions on depression are rare and very few if any such studies have been performed on patients with chronic somatic states. In this study, we aimed to describe and compare the iCBT and ODF groups with regard to healthcare use and to identify factors impacting healthcare use in these groups. We found that both the iCBT and ODF groups had a high level of healthcare use (especially outpatient clinic/primary care contacts) the year prior to the intervention. The year post intervention, the healthcare use had decreased by approximately one third in both groups. However, this was not significantly different between the groups. Interestingly in the iCBT group only, lower levels of depressive symptoms post intervention were associated with a decrease in the number of outpatient clinic and/or primary care contacts.
We found that the use of outpatient services the year prior the intervention (31 for iCBT and 37 for ODF) was in both groups higher than was reported for CVD patients in a previous cross-sectional study (23). In that study, patients with myocardial infarction had 10 contacts and patients with Angina Pectoris 17 healthcare contacts. We did not measure depression the year prior the intervention, but it is not uncommon that depression in CVD patients can become chronical since depression seldom is detected and that patients are not offered treatment (8). A possible explanation behind the high use of outpatient services the year prior the intervention in our sample could therefore be due to depression. The association between mental health disorders and increased healthcare use among patients with chronic diseases has been noted in previous research (4–6). It is also known that the addition of depression to CVD carries a higher risk for healthcare use, in particular for those with chronic depression (8). Morrissey (24) found in a population-based study of 791 individuals with CVD that the addition of a non-related comorbidity (such as depression/anxiety) led to a three times higher risk for use of outpatient services, such as general practitioner visits, and 1.5 times higher risk for use of inpatient services. In our study, most of the contacts within outpatient/primary care clinics were to physicians and primary care nurses. Hence, as depression is one of the most important factors associated with increased healthcare use in CVD patients, this indicates a need to optimise the management of depression in these patients. When performing interventions that target depression in CVD patients, Palacios et al. (8) suggested that these should focus the impact on depression and healthcare use in CVD outpatients.
We have previously reported that 9 weeks of iCBT compared to ODF (i.e., an active control group) had significantly better effects on depressive symptoms and HRQoL in CVD outpatients (15). In the present study we reported the effect on healthcare use. The number of admissions was relatively low in both groups, before as well as after the intervention, and it is therefore hard to identify any differences between the groups. The number of hospital admissions was 0.8 in the iCBT and 1.1 in the ODF groups prior the intervention, and the year post intervention this had decreased to 0.6 in both groups. The low number of hospital admission, especially in the iCBT group may also explain why only a significant decrease was detected in the ODF group. We found that both groups had a significant decrease in number of outpatient clinic and/or primary care contacts the year post intervention by approximately 30%, but no differences could be found between the groups (Table 3). The difference between numbers of in- and outpatient service use is mostly due to the structure of the Swedish healthcare system, were primary care serves as the first check point and people are initially referred there for consultation regarding their care needs (25). Suggesting that interventions targeting depressive symptoms in CVD are more likely to have impact on the number of outpatient clinic and/or primary care contacts than the number of hospital admission.
We could not find that iCBT was superior to ODF in decreasing the use of healthcare services. A similar finding was reported in the meta-analysis by Kolovos et al. showing that iCBT compared to control was not more cost-effective (12). Still, the finding that iCBT at first sight does not seem to have any health-economic benefits may be related to the design of the control conditions. In our study iCBT was compared to an active control group (i.e. ODF). After completion of ODF, all patients were offered iCBT. This design was due to ethical reasons, and 38% of them accepted and received iCBT. In the meta-analysis some of the five studies also used more active control approaches such as psychoeducation, care as usual and a self-help booklet or a waiting list and who also received iCBT (12).
In our study, patients in the control group were involved in a discussion forum that enabled them access to other CVD patients´ experiences, tips, and support, and hypothetically also a reduced need of support from healthcare services. Other studies (26) also show that active control approaches have impact on depressive symptoms and makes it harder for iCBT to demonstrate a greater impact on healthcare use. As mentioned, those in the ODF group also received iCBT. This could explain why both iCBT and ODF groups showed a decrease by 30% in healthcare use. Having in mind that most CVD patients with depression in real life are not detected or receive any treatment, Celano et al. (27) argues that iCBT in CVD patients would lead to health-economic benefits.
We also demonstrated that lower depressive symptoms scores post intervention were associated with a decrease in the number of outpatient clinic and/or primary care contacts, in favour of the iCBT group. This indicates that lower levels of depressive symptoms, that in a significantly higher extent were achieved by the iCBT group compared to ODF (15), resulted in a decrease in outpatient service use. In the ODF group, improved HRQoL as measured by MCS12 scores post intervention was moderately associated with a decrease in number of hospital admissions. This association was not found in the iCBT group. Since impaired HRQoL has been associated with increase in hospital admissions in CVD (28), the improved HRQoL in the ODF group might explain the significant decrease of 45% in hospital admissions.
Since our control group was an active control and of which one-third also received iCBT post-intervention, we cannot exclude the possibility that iCBT has health-economic benefits and may have reduced the differences between the groups regarding healthcare use. Based on the intervention group including 72 patients, the time consumption for a therapist in the iCBT program was about 13 minutes per patient per week, which sums up to two hours per patient for the nine weeks treatment and to 140 hours for the whole iCBT group. Face-to-face CBT is normally at least 10 sessions/weeks with about 45 minutes per session. The time needed for treating 72 patients would therefore sum up to 540 hours for the whole treatment. By using the Internet to deliver the CBT treatment, the time saving would correspond to about 400 therapist hours. Above this, there are other savings in relation to the patients and society in general since the treatment can be performed when suitable for the patients without travel expenses to healthcare facilities or lost working hours for therapist appointments. Thus, iCBT for depressive symptoms in CVD seems to be cost-saving, but in order to draw the correct conclusions, a cost-effectiveness analysis needs to be carried out.