# Toward a Comprehensive Understanding and Evaluation of the Sustainability of E-Health Solutions
## 4 Results  
In this section, we present the findings of the SLR. First, an overview of the selected studies is presented. Then, the findings are discussed in terms of e-health sustainability definitions, dimensions and elements, and assessment methods. The study selection process took place in February 2021 and then updated in November 2022.  
In the first search round, a total of 4811 papers were obtained by applying the search string in three chosen digital libraries (i.e., Web of Science, IEEE Xplore, and Scopus) in addition to 16 studies retrieved by the snowballing technique, as shown in Figure 2. The title and abstracts of all papers that appeared in the search results of the selected libraries were checked for relevancy, and if found to be relevant, they passed to the second round. Of the 4811 papers, 125 papers passed to the second round, that is, the reading of the entire paper (see Figure 1), as many papers found were deemed irrelevant. This is due to the polysemy of some keywords in the search string, such as the term \"long-term\", that was used in this SLR as a synonym of sustainability. Nonetheless, \"long-term\" is used in the healthcare context to refer to the technologies that are used to help people with chronic diseases and need a \"long-term\" healthcare provision. Therefore, such papers were excluded in the first round.  
\begin{table}
\begin{tabular}{l} \hline
3.3 E-health Solution \\ \hline \(\bullet\) & E-health solution type \\ \(\bullet\) & Focus of e-health solution \\ \(\bullet\) & Replace an existing process? (Y/N) – if no, it means it works to align with a process, or provides a new service. \\ \(\bullet\) & Status (running, proposed, etc.) \\ \(\bullet\) & Users (e.g., patients, nurses, physicians, staff, etc.) \\ \(\bullet\) & Benefits \\ \hline \end{tabular}
\begin{tabular}{l} \hline
3.4 Assessment Methods \\ \hline \(\bullet\) & Existence of assessment method (yes/no) \\ \(\bullet\) & Method (model, framework, diagram, etc.) \\ \(\bullet\) & Type of the assessment methods (standards, formula, checklist, etc.) \\ \(\bullet\) & List of assessment methods \\ \(\bullet\) & Used for which aspects? \\ \(\bullet\) & Source (literature, proposed, etc.) \\ \hline \end{tabular}
\begin{tabular}{l} \hline
3.5 Evaluation/Validation \\ \hline \(\bullet\) & Evaluated/validated? \\ \(\bullet\) & Method (with experts, case study, etc.) \\ \(\bullet\) & Number of iterations \\ \(\bullet\) & Duration \\ \(\bullet\) & Context \\ \hline \end{tabular}
\begin{tabular}{l} \hline
3.6 Additional Information \\ \hline \end{tabular}
\end{table}
Table 5: _Cont._Simultaneously, the backward snowballing approach was conducted in the first and second rounds to collect relevant studies that were not included in the digital libraries' results. In the second round, all 125 papers that passed the first round were read fully and then compared against the inclusion and exclusion criteria. Only 22 out of 125 papers passed the second round. The rest were eliminated because they did not meet the inclusion and exclusion criteria presented in Tables 2 and 3. The third round was conducted, and all 22 papers passed the quality assessment.