Data collection tool

3.1.1 Development of the online questionnaire Generic questionnaire unmet needs

The questionnaire used in the current study is based on the generic questionnaire developed in the context of KCE project 2017-14-HSR-unmet needs^e. The full methodological details of the development of this generic questionnaire will be published in this report (publication expected early 2022). In summary, the questionnaire was developed starting from a literature review that identified the most common methods to measure unmet medical needs. All these methods were listed and broad dimensions were identified. For each dimension, the KCE research team listed the appropriate questions from the initial methods. In some cases, questions were reformulated to meet the generic nature of the questionnaire. The draft questions were submitted to a Delphi panel consisting of patient representatives (from umbrella organisations of patient associations and sickness funds) to find a consensus on the relevance and clarity of each question and the completeness of the questionnaire.

Adaptations made for long COVID

For the purpose of the current study, the generic questionnaire was adapted to the long COVID condition, by reformulating some questions (e.g. using

“long COVID” instead of the generic term “your disease”) and by adding questions that are specific for long COVID (See Supplement to Chapter 4).

The adaptations were based on a quick scan of the literature5, 60, 87, 195-197

and a pragmatic review about the epidemiology of long COVID (definition, prevalence, range and frequency of symptoms and risk factors).⁹

KCE Report 344 Long COVID – Scientific report 113

Translation and face-validity

The questionnaire was first developed in French and afterwards translated to Dutch by KCE researchers. A comparison of the two versions was carried out to ensure that both versions were identical in terms of structure and content. Subsequently, both versions were proofread by team members, two representatives of patient umbrella organisations (one French-speaking (i.e.

LUSS) and one Dutch-speaking (i.e. VPP)) and one researcher of Sciensano.

Online version: Patient Survey

Once the versions were proofread by the KCE research team, they were imported into an online platform (LimeSurvey hosted on the KCE server) in both languages. To pre-test the survey on the understandability of the questions and the user-friendliness of the online version, KCE researchers recruited five non-scientific citizens with different ages and backgrounds.

The online questionnaire was adapted based on their feedback. Finally, KCE team members pre-tested the online version in French and Dutch.

Unfortunately, despite all quality checks, the response categories for the variable ‘age’ were programmed differently in the Dutch and French questionnaire.

• Dutch: < 18y; 18-24y; 25-44y; 45-64y; 65-74y; 75y+

• French: < 18y; 18-30y; 31-40y; 41-50y; 51-60y; 60y+

As a consequence, we reported the age of respondents seperatly for the French and Dutch respondents.

Ethical committee approval

Before launching the questionnaire, the research protocol, including the questionnaire, was submitted to and approved by the ethical committee of the ‘Cliniques Universitaires de Bruxelles’ (P2020/704 / B40620200000319).

The approval was valid from 15/01/2021 till 30/11/2021.

3.1.2 Final questionnaire

Study introduction and patient approval

The questionnaire begins with a box explaining to the participants the purpose of the survey, the steps that follow the survey, and the requirements for completing the online questionnaire (inclusion criteria – see further).

Then, respondents were asked to give informed consent before participating.

The online questionnaire includes 33 questions structured around 5 main topics

The questionnaire consisted of 33 questions (long COVID specific questions are identified by an *) organised around the following themes:

• General information: a distinction was made between people who were answering for themselves, for another adult (unable to answer the questionnaire him/herself) or for a minor. The other questions in this section related to demographic characteristics of the respondents:

gender, age, place of residence (province), level of education and employment status (paid employment, disability, health sector employment);

• Acute episode of COVID-19*: this section was designed to provide information on the respondents' experience during the acute phase of COVID-19: how and by whom they were diagnosed; whether they were hospitalised (general COVID or on intensive care unit; with or without ventilation) and the duration of their hospitalisation; presence and duration of COVID-19 symptoms;

114 Long COVID – Scientific report KCE Report 344

• General health status: this section aimed at comparing respondents' health status before and after COVID-19*^f, using the EQ-5D-5L^g as quality of life instrument. The EQ-5D-5L asks respondents to describe their health status on five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each item had five response categories, reflecting the level of problems experienced in each dimension (no problems, slight problems, moderate problems, severe problems, extreme problems). In addition, respondents are asked to score their health state before and after COVID-19 on a visual analogue scale, ranging from 0 (worst imaginable health state) to 100 (best imaginable health state);

• Other illnesses: the aim of this section was to find out whether respondents had comorbidities and if so, which one(s). For this purpose, a non-exhaustive list was proposed, as well as an open field, where respondents could mention other comorbidities that were not included in the list;

• Long COVID*: the questions in this section aimed at describing the physical, psychological and care consequences of long COVID. The questions addressed the symptoms (physical and psychological) experienced by the respondents; the use of and access to care; the financial consequences of long COVID; the level of information sought and received by the respondents; and the treatments together with their medium and long-term effects.

Combination of pre-defined response categories and open field For most of the questions, respondents were given a choice of answers (often based on the literature) but they were also given the opportunity to add elements in an open field. Open field responses were analysed using thematic coding and afterwards recoded into existing categories (if

f The generic questionnaire did only foresee to question the health status once.

Since long COVID is preceded by an acute phase the health status might have changed rapidly. Therefore it was decided to ask the current perceived health status as well as the health status before COVID-19.

possible). To create these categories, we retained the main idea(s) contained in each participant's response; if the response could be interpreted in different ways, we classified it in the 'Other' category to avoid misinterpretation.

For several questions, respondents were asked to indicate their level of satisfaction. In many instances, responses to specific questions led to new sub-questions (e.g. when the respondent indicated 'Yes', he/she had to specify his/her answer). In addition, all comments that did not answer the question posed were classified as 'Not applicable'.

Last question: recruitment candidates for online forum or in-depth interviews

At the end of the questionnaire, participants were asked whether they were willing to participate in either the online discussion forum, or an individual interview or none of these two (cfr infra).

3.2 Participants

Recruitment of the participants

Several communication channels (KCE website, e-mailing, social networks, general media and long COVID patient support groups) were used to reach the target population. The call for participation included a link to a page on the KCE website where the same communication was available and the link to the survey and informed consent was accessible. Patients who recognised themselves in the description of the call for participation could directly access the online survey via the link on the KCE webpage. In addition, we asked the sickness funds, the umbrella patient organisations (LUSS and VPP) and the general media (press conference, COVID-19 crisis centre) to share the information.

g https://euroqol.org/eq-5d-instruments/eq-5d-5l-about/ (last access: 18 June 2021)

KCE Report 344 Long COVID – Scientific report 115

In- and exclusion criteria

Respondents had to meet the following criteria to participate in the survey:

• been infected with COVID-19 (self-declared or based on a test) ;

• not or no longer hospitalised at the time of the survey;

• having, at the time of the survey, long COVID symptoms or having had COVID symptoms for more than 4 weeks after the onset of the COVID-19 disease;

• living in Belgium.

When the respondent represented another adult (who met the inclusion criterion but was unable to respond his- or herself because of his/her health condition) or a minor who met the inclusion criteria, he/she had to respond as if the patient he/she represented would answer the questionnaire.