All children with CF and PCD and their primary caregivers who were referred to four pediatric pulmonology centers and agreed to participate in the study were recruited between July 2017 and September 2019. Informed consent forms were obtained from the primary caregivers before data collection. The study was performed according to the principles of the Declaration of Helsinki and approved by the Ethics Committee of the Faculty of Medicine (No. 2017/984; June 16, 2017). CF was diagnosed with genetic analysis and/or sweat chloride test, and PCD was diagnosed with genetic analysis and/or high-speed video microscopy and/or transmission electron microscopic examination, and clinical findings.

Questionnaires regarding the children’s clinical features and demographic data about the children and their families were administered to the caregivers. Information collected about the children included age, sex, ethnicity, body mass index (BMI), pulmonary function tests (PFT) results, history of sibling death, follow-up duration, number of hospital visits (both emergency and outpatient clinics) and hospitalizations in the previous 6 months, duration of hospitalizations in the previous 6 months, and the number of exacerbations in the last year. Information on the presence of bacterial colonization in the sputum culture of children both during hospitalization or outpatient clinic visits were obtained from their medical records. Colonization was defined as bacterial growth in a sputum sample with no clinical signs or symptoms.¹³ In the children’s PFT results who were adaptable to PFT technique, FEV₁ (forced expiratory volume in the first second), FVC (forced vital capacity), FEF_25-75 (25-75% of forced expiratory flow) percent predicted by age, and FEV₁/FVC values were obtained from their medical records. The PFTs were performed according to the American Thoracic Society-European Respiratory Society ATS-ERS guidelines.¹⁴

Data of the caregivers were obtained from the demographic questionnaire. Information on factors that might affect the psychological status of the caregiver was collected such as their ages, ethnicity, higher education levels, occupational status, family income, physical or psychiatric disorders and treatments, consanguinity, the number of children, chronic disease in another child (if any), family type (nuclear or extended), the family members who were the primary caregivers, any persons helping with the children’s care (defined as assistants), and any work or family problems (such as dismissal, inability to care for other children, parental problems) related to the children’s hospitalization. Monthly family income levels were classified as below the hunger threshold, between the hunger and poverty thresholds, and above the poverty threshold according to 2016 data of the Turkish Statistical Institute.¹⁵ The occupational status of the mothers was classified as homemakers, and blue and white-collar workers. Salaried professionals, which refers to general office workers and management, were defined as white-collar workers. Workers who performed manual labor, earned hourly wages or were paid piece wages according to the amount of work done were defined as blue-collar workers.

The Beck Depression Inventory (BDI), Maslach Burnout Inventory (MBI), Zarit Caregiver Burden Scale (ZCBS), and the Parental Attitude Research Instrument (PARI) were used for psychological measurements and attitudes towards the children of the primary caregivers. The Turkish versions of these scales have been validated and used in many previous studies.^16-19 The modified Shwachman-Kulczycki Score (mSKS) was used for evaluating the clinical status of children with CF.

The BDI consists of 21 items and measures symptoms related to emotional, cognitive, physical, and motor functions in depression. The overall depression score was obtained by summing all the items’ scores. Cronbach’s alpha value of the inventory was found as 0.80.¹⁶ Scores between 0-9 were classified as no depression, between 10-18 as mild depression, between 19-29 as moderate depression, 30 and above as severe depression. The scores that can be obtained from the scale vary between 0-63.²⁰

The MBI assesses burnout and consists of 22 items divided into three subscales: emotional exhaustion, depersonalization, and personal accomplishment. Emotional exhaustion indicates the stress dimension of burnout and refers to a decrease in the individual’s emotional and physical resources. Depersonalization represents the interpersonal dimension of burnout and refers to negative, rigid attitudes toward people, and unresponsiveness to work. Personal accomplishment refers to the sense of competence and achievement in one’s work. A low score indicates that the person tends to evaluate themself negatively. Cronbach’s alpha value of the inventory was found as 0.93.^17,21 Each subscale was scored according to the reference ranges of the MBI: for emotional exhaustion, between 0-16 as low, between 17-26 as moderate, 27 or above as high; for depersonalization, between 0-6 as low, between 7-12 as moderate, 13 or above as high; for personal accomplishment, 31 or less as low, between 32-38 as moderate, and 39 or above as high. The total scores obtained range from 0-54 for emotional exhaustion, 0-30 for desensitization, and 0-48 for personal accomplishment. Burnout was defined using the updated Maslach-recommended criteria of “high emotional exhaustion and high depersonalization” or “high emotional exhaustion and low personal accomplishment”.²²

The ZCBS consists of 22 items and assesses caregivers’ perceived burden. Each item is scored on a 5-point Likert scale (0=never , 1=rarely , 2=sometimes , 3=quite often , 4=almost always ). A total score between 0-20 points indicates no burden, between 21-40 illustrates mild burden, between 41-60 shows moderate burden, and between 61-88 points indicates severe burden. Cronbach’s alpha value of the ZCBS was found as 0.83.^18,23

PARI was used to determine the attitudes of caregivers towards their children. PARI, which is a Likert-type scale, consists of 60 items and five subscales. These subscales are over-protectiveness, democratic attitude, rejection of the homemaker role, marital conflict and strictness. For each statement, one of the options ”I find it very appropriate” (4), ”I find it quite suitable” (3), ”I find it somewhat appropriate” (2), ”I do not find it suitable at all” (1) is selected. The option number marked for each item is evaluated as the item score. Responses to items 2, 29, and 44 are scored in reverse. A separate score is obtained for each subscale. There is no total score. A high score from the subscale indicates that the attitude reflected by that dimension is approved. The highest scores that can be obtained from the subscales are 64 for over-protectiveness, 36 for democratic attitude, 52 for rejection of the homemaker role, 24 for marital conflict, and 64 for strictness. Except for democratic attitude, high scores from the subscales indicate the presence of a negative parental attitude. The Cronbach’s alpha coefficient of the scale was found as 0.89.^{19, 24}

The mSKS is calculated in four domains, including general activity, physical examination findings, nutritional status, and radiological findings. Each parameter was scored from 5 (i.e. severely impaired) to 25 (i.e. normal), which resulted in a total score categorised as excellent (86-100), good (71-85), mild (56-70), moderate (41-55) and severe (<40).^25,26

In the descriptive statistics section, categorical variables are presented as numbers, percentages, and continuous variables as mean ± standard deviation and median (range). Pearson’s Chi-square test and Fisher’s exact test were used to evaluate categorical variables. The Mann–Whitney U test was used for comparative analysis between two independent variables for data that did not conform to normal distribution, and the independent sample t-test was used for data with normal distribution. In comparisons of three and more variables, one-way analysis of variance (ANOVA) was performed where parametric test conditions were ensured, and the Kruskal–Wallis H test was performed where parametric test conditions were not ensured. The relationship between data that did not conform to normal distribution was evaluated using Spearman’s correlation test, and data with normal distribution were evaluated using Pearson’s correlation test. P-values less than 0.05 were considered statistically significant.