Participants and procedure
Recruitment to the study and data collection were conducted on-line between July and October 2020. Over this period, direct methods of interaction with participants for research purposes were impossible because of COVID-19-related restrictions.
Two independent methods of recruiting participants were used. The first was the Polish on-line panel ARIADNA. The description of the study did not specify its purpose and eligible participants were qualified to the study if they gave an affirmative answer to one of the questions regarding diagnosis of the chronic diseases which were the target of this study.
The second method of recruitment was an online survey created in Google Forms, which was advertised on various on-line forums and through foundations dedicated to supporting people with specific diseases (see: Acknowledgments).
Participants were enrolled into the study if they reported being at least 18 years old and answered affirmatively regarding the medical diagnosis of one of the following diseases: rheumatoid arthritis (RA), asthma, hypothyroidism, diabetes (both types), hypertension, psoriasis, or systemic lupus erythematosus. Since the obtained sample sizes of participants with psoriasis and systemic lupus erythematosus were too small (n = 20 and n = 18, respectively), the data from these groups of participants were not included in the analyses. The final study sample consisted of 505 participants: 64 people with rheumatoid arthritis, 87 people with asthma, 130 people with hypothyroidism, 101 people with diabetes (both types), and 123 people with hypertension.
Questionnaires
The following variables were controlled in the study:
Sociodemographic variables:
- gender (male/female/other)
- age expressed in years
- relationship status (married/in informal relationship/single)
Clinical variables:
- time since diagnosis of the disease (in years)
- number of hospitalizations in the last 12 months
Cognitive Appraisal
Illness-Related Appraisals Scale - Revised (Pankowski, Wytrychiewicz-Pankowska, & Janowski; 2021): this self-report scale consists of 30 questions to which the respondent answers on a 5-point scale. This tool consists of the following scales (ratings): Loss (α = 0.93), Harm (α = 0.95), Benefit (α = 0.9), Challenge (α = 0.9), Value (α = 0.9), and Threat (α = 0.94). Additionally, 5 questions were added regarding the importance that the respondent attaches to their own illness (Importance scale). The reliability of the Importance scale was α = 0.79. For details about this scale, see Appendix 1.
Illness-Related Beliefs
The Illness-Related Beliefs Questionnaire (IRBQ; Pankowski, Wytrychiewicz-Pankowska, & Janowski; 2021, Pankowski et al., 2021) was used to assess the intensity of a patient's personal beliefs about key aspects of their chronic disease. It consists of 13 IRBs covering five categories of beliefs previously described in the literature and several additional IRBs (such as those regarding self-knowledge, comparisons to other patients, social stigma, etc.). Each belief is expressed on a continuum ranging from one extreme to another. Respondents were asked to locate their own personal belief on this continuum using a 1–10 response scale. The scores endorsed by the respondents for each belief are treated as separate scales and do not yield one cumulative total score. For details about this scale, see Appendix 2.
Indicators of Adaptation to Chronic Illness
The Acceptance of Life with the Disease Scale (ALDS; Janowski et al., 2012) is a self-report questionnaire used to measure the degree of acceptance of one’s life with a disease. It consists of 12 test items divided into three subscales: (1) Satisfaction with Life Despite the Disease (α = 0.9); (2) Reconcilement with the Disease (α = 0.89); and (3) Self-distancing from the Disease (α = 0.9). A global score can be calculated, which is the sum of the scores obtained for all items (α = 0.95).
Beck Depression Inventory – I (BDI-I); original version by Beck et al. (1961), Polish version by Parnowski and Jernajczyk (1977). The BDI-I is a self-report scale that assesses the presence of depressive symptoms. It contains 21 depressive symptoms, the severities of which are described by four statements. Each statement is assigned a score from 0 to 3 points. Apart from the global score, two subscales can be calculated (Cognitive-Affective and Somatic Symptoms). For the purposes of descriptive statistics, the numbers and percentages of people who did not exhibit clinically significant depressive symptoms (<10 points), as well as mild (≥ 10 and <20), moderate (≥ 20 and <30), and severe (≥30) depressive symptoms were also calculated (Łopuszańska et al., 2013). The number of people who presented suicidal thoughts (1 point on question "I") and tendencies (2 or 3 points on question "I") were also taken into account. The Cronbach’s alpha reliability coefficient of the BDI global score in our study was high (α = 0.93); the reliability coefficients of the Cognitive-Affective and Somatic Symptoms scales were α = 0.92 and 0.82, respectively.
Statistical Analyses
First, the statistical significance of differences between groups of people distinguished based on chronic illness was calculated in terms of IRBs, CA, severity of depressive symptoms, and level of acceptance of living with the disease using ANCOVA, controlling for sociodemographic (sex, age, relationship status) and clinical (time since diagnosis, number of hospitalizations in last 12 months) variables. Additionally, marginal means with Bonferroni correction were estimated to compare the results from participants with particular diagnoses in pairs. All further analyses were first performed for each medical diagnosis separately, and then together for all respondents.
In the next step, partial correlations between measured variables were computed, controlling for sociodemographic (sex, age, relationship status) and clinical (time since diagnosis, number of hospitalizations in last 12 months) data.
Due to the fact that somatic symptoms of depression assessed using the BDI-I Somatic Symptoms scale may also be due to the symptoms of chronic illness (e.g., sleep problems in RA patients may be due to pain, rather than depression), it was decided to use only the BDI-I Cognitive-Affective symptoms scale in further analyses.
Next, we determined the statistically significant, specific contribution of cognitive variables to explaining the variance in adaptation indices (cognitive-affective symptoms of depression and the acceptance of living with the disease global score). For this purpose, a hierarchical regression analysis was used, in which subsequent variables were entered in the following blocks:
- sociodemographic variables (gender, age, relationship status);
- clinical variables (time since diagnosis, number of hospitalizations within the last 12 months);
- CA;
- IRBs.
Due to the fact that the result indicates a specific contribution to explaining the variance of only the variable entered in the last block, calculations were also performed using CA as the last variable.
The last step was to perform stepwise regression analysis to determine statistically significant predictors of adaptation to living with the disease. Adaptation indicators were placed as dependent variables, and all other variables were placed all together in one block.
Ethical Approval
This study was conducted according to the guidelines of the Declaration of Helsinki. Approval from the local Institutional Ethical Committee at the first author’s University was obtained for this study. Informed consent was obtained from all participants upon enrollment.