Overview of DiHA included in the German DiHA directory
As of February 2022, 30 digital health applications were listed in the DiHA directory of BfArM. The majority of the applications (n = 20) had been conditionally included while ten DiHA were listed permanently (23). Additional file 1 gives an overview on DiHA listed in the directory. Two-thirds of DiHA were admitted in 2021 (n = 18), one-third in 2020 (n = 10) and two DiHA in early 2022. The manufacturers are most often start-up companies, small to partly medium-sized companies. Employee numbers range up to 140. Almost half of the DiHA are web-only apps, 13 Apple iOS and Google Android apps only and 3 are accessible via all platforms.
Although most DiHA were in the therapeutic field of mental illness, with the help of cognitive behavioral therapy, the clinical conditions that can be treated with DiHA were diverse and ranged from tinnitus therapy, self-management for diabetes to therapies for obesity (Fig. 4).
No additional equipment external to the application itself was necessary for most (n = 28) DiHA. This is important as additional equipment has to be paid out of pocket by patients. For the Rehappy DiHA there is an activity tracker as an additional device, and for the zanadio DiHA there are some optional additional devices. Two thirds of the DiHA (n = 22) were only available in German language; only some in one additional language (n = 4) and several languages (n = 4).
The costs of DiHA covered by SHI are listed in the directory. There are always start-up costs (costs for start-up package) and partly costs for a use for 90 days. In some cases, there are cost for an additional 90 days of use (n = 4). Overall, the average price is € 443.80 per quarter with a price spectrum ranging from € 119.00 to € 743.75. The most expensive DiHA thus cost 6.3 times as much as the cheapest. The average cost of a DiHA permanently listed is € 469.82 per quarter (min = € 203.97, max = € 743.75). The average cost of the DiHA listed conditionally is € 430.80 per quarter (min = € 119.00, max = € 718.20). Figure 5 shows the cost of all DiHA in time trend by half-year. The prices are quite far apart in all half-years and increase slightly.
Evidence on care effects for DiHA conditionally included in the registry
With the requirement to provide evidence of positive care effects, 20 DiHA were provisionally listed (Additional file 1). For the DiHA CANKADO PRO-React Onco, an RCT is ongoing (NCT03220178). For the DiHA Novego, three RCTs were already published (24–26) (Moritz et al. 2016; Beiwinkel et al. 2017; Miegel et al. 2019) and another RCT is currently ongoing. For the other DiHA, the current evidence is limited to efficacy data, systematic data evaluations, preliminary studies, and “data from a sample”. For all DiHA, an assessment of the medical benefit is planned. For five DiHA (CANKADO PRO-React Onco, Cara Care für Reizdarm, Kranus Edera, Mindable, Rehappy), an additional demonstration of patient-relevant structure and process improvement such as health literacy, patient sovereignty, adherence, and patient satisfaction is planned. The manufacturers of the DiHA provisionally included state that they want to conduct studies such as prospective RCT (n = 19), or a multicentre, prospective, two-arm study (Cankado) (n = 1).
Evidence on care effects for DiHA permanently included in the registry
Table 2 gives an overview on permanently listed DiHA (n = 10), and the evidence used in the fast-track pathway. This includes the level of evidence of studies, intervention and control group, and results of outcomes split into the evidence on medical benefit, patient relevant structure and process outcomes. RCTs were conducted for all DiHA with two studies still in the process of publication (Kalmeda and Vivira).
Medical benefit was investigated and demonstrated for all DiHA. Outcomes mostly include morbidity as reduction of the disease symptoms, and partly quality of life. Further effects on care were demonstrated in studies of two DiHA, including reduced therapy-related costs and burdens for patients and their relatives, and increased patient sovereignty. The outcomes were assessed with different survey instruments. These were partly validated instruments, such as Patient Health Questionnaire-9 (deprexis, Kalmeda) or the General Depression Scale (HelloBetter Diabetes and Depression) or the Hospital Anxiety and Depression Scale (Elevida).
The intervention in the studies was the app with and without e-mail-support, the app with and without scheduled e-mail contact with a therapist, a web-based therapy, or care as usual and the app. The control group was either “Waitlist control” or “Care as usual”. Intention to treat analyses were performed to investigate effects for eight DiHA. Randomised group allocation was performed in all studies of the ten DiHA (Table 2).
Classification of DiHA
In Fig. 6, DiHA are assigned in the classification scheme, which is intended to determine the required level of evidence for DiHA to be evaluated (19). In some cases, multiple assignments are available if a DiHA could not be clearly assigned. According to the classification scheme, most DiHA were assigned to the target group "chronically ill, stable health" and "high risk/unstable health", one to the target group "Healthy with risk factors". DiHA for people with mental illnesses, such as depression, anxiety or panic disorders, were assigned to the group "chronically ill, stable state of health", but could also be assigned to the group "highly vulnerable/unstable health status".
Regarding the functions, the classification is not always completely clear-cut. Double assignments are possible in some cases. Decisions on classification were made based on the priority function. In most cases, the function of the DiHA was “treatment” and, more specifically, "indirect intervention (self-management)". This function is present 22 times, while simple monitoring applies to two DiHA.
According to the classification, 63% (n = 19) of the permanently and conditionally included DiHA fall into a medium requirement level requiring a control group and intention-to-treat analysis, but not randomisation (Fig. 5 and Additional file 1), while 37% (n = 11) fall into the high requirement level necessitating randomisation. Regarding permanently included DiHA (n = 10), for six DiHA the highest requirement level would have been required.
The categories "Diagnosis", "Complex monitoring" and "Direct intervention", which all correspond to a high requirement level, are not yet occupied. Nevertheless, manufacturers of all (n = 10) DiHA permanently included in the directory conducted a randomised controlled trial.
Study assessment
Risk of bias in 11 published RCTs of 8 permanently included DiHA was assessed based on the RoB II tool (22). The agreement rate between the two assessors (HL, HE) across all studies was 93.4 %.Studies of two DiHA were at the time of assessment in publication process (Kalmeda and Vivira). A total of 9 out of 11 RCTs were judged to be at high risk of bias and two studies raise some concerns. For graphical representations of overall risk of bias per assessment category in included studies see Fig. 7. A justification of the evaluation can be found in the Additional file 2.
Randomisation
The randomisation process was associated with a low risk of bias in three studies. These studies showed random allocation sequence generation and concealed allocation. About two-thirds (7/11) of the studies were associated with some concerns as no information on the allocation sequence was available. One study (27) resulted in a high risk of bias, as baseline differences between intervention groups suggest a problem with the randomisation process.
Deviation from the intended intervention
For deviations from intended interventions, almost all studies (10/11) had low risk of bias, as no deviation from the intended intervention was observed. Almost all authors conducted an intention-to-treat analysis. The authors of one study (28) did not provide information on the analyses conducted to estimate the effect of assignment to intervention.
Missing outcome data
For around two-thirds of the studies (7/11), there was substantial amount of missing outcome data. There is reason to suggest that the missingness in the outcome is related to its true value, which is why the potential for bias in this category was estimated to be high. Two studies (29, 30) performed sensitivity analyses and had a low risk of bias in the domain. In two studies (31, 24), it was not likely that missingness in the outcome depended on its true value - this led to some concerns.
Measurement of the outcome
All eleven studies have some concerns as participants' knowledge of their assignment to the intervention or control could theoretically lead them to over- or understate their outcome measurements; however, there is no evidence that such bias has occurred.
Selection of the reported results
More than half of the studies (6/11) had a low risk of bias in the selection of the reported results, as a pre-specified protocol was provided, and data produced was analysed in accordance with the pre‐specified analysis plan. Almost one third of the studies (3/11) raised some concerns as it remains unclear if selective reporting occurred. One third of the studies (3/11) had a high risk of bias as outcomes that were supposed to be investigated according to the protocol were not mentioned in the study or were not evaluated.