Data collection and instruments

Data were collected by one researcher for all patients using standardised structure interview in the period from July 2019 to January 2020. The data collection questionnaire included: sociodemographic and clinical characteristics part, HRQoL Questionnaire, State-Trait Anxiety Inventory, and Mishel’s Uncertainty of Illness Scale. Data were collected using a structured interview format by one trained researcher for all patients.

Respiratory HRQoL Questionnaire-C version

The Arabic version ²⁸ of the St. George’s Respiratory Questionnaire, C version (SGRQ-C), was used to measure HRQoL among patients with respiratory disease like COPD and asthma. ²⁹ The original SGRQ-C contains 17 items and three subscales that are: symptoms (items 1 to 8), activity-related (items 11 and 15), and impact-related (items 9, 10, 12 to 14, 16 and 17). Higher scores in the total SGRQ-C and sub-scales indicate a decrease in quality of life. The scale’s validity and reliability was established. ³⁰ Cronbach’s alpha internal consistency of the scale was 0.95 and the long-term test–retest reliability ranged from 0.70 to 0.86. ^{28, 30– 32} The internal consistency (Cronbach’s alpha) of the Arabic version of SGRQ-C in this study was 0.83.

Mishel’s uncertainty of illness scale

Mishel’s uncertainty of illness scale (MUIS) was used to assess uncertainty related to disease trajectory. It consists of a 23-items using a five-point Likert scale (strongly agree to strongly disagree). The level of illness uncertainty increased as the total score increased. The uncertainty total score also can be divided into three levels: mild (23–53), moderate (54–84), and high (≥85). ³³ The scale has a Cronbach alpha of 0.74–0.92. ^{22, 24} The Arabic version ³⁴ was used in the study. Internal consistency (Cronbach’s alpha) of the Arabic version of MUIS-C in this study was 0.86.

State- Trait Anxiety Inventory (SAI)

The SAI ³⁵ consists of 20 self-reported items that measure patients’ situational anxiety levels. The SAI has responses 1–4 where one means “not at all”, two “somewhat”, three “moderately so”, and four “very much so”. The total scores can range 20–80: a higher total score indicates increased level of anxiety. ³⁵ The Cronbach’s alpha coefficient for the STAI was 0.92. ³⁵ The internal consistency (Cronbach’s alpha) of the Arabic version of SAI in this study was 0.94. Permission to use the SAI was obtained from the copyright holder Mind Garden, Inc. ³⁶