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Abstract Background The Minimal Clinically Important Difference (MCID) assesses what change on a measurement tool can be considered minimal clinically relevant. Although the recall period can influence questionnaire scores, it is unclear if it influences the MCID. This study is the first to examine longitudinally the impact of the recall period of an anchor question and its design on the MCID of COPD health status tools using the COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ) and the St. George’s Respiratory Questionnaire (SGRQ). Methods Moderate to very severe COPD patients without respiratory co-morbidities were recruited during 3-week Pulmonary Rehabilitation (PR). CAT, CCQ and SGRQ were completed at baseline, discharge, 3, 6, 9 and 12 months. A 15-point Global Rating of Change scale (GRC) was completed at each follow-up. A five-point GRC was used as second anchor at 12 months. Mean change scores of a subset of patients indicating a minimal improvement on each of the anchor questions were considered the MCID. The MCID estimates over different time periods were compared with one another by evaluating the degree of overlap of Confidence Intervals (CI) adjusted for dependency. Results In total 451 patients were included (57.9 ± 6.6 years, 65% male, 50/39/11% GOLD II/III/IV), of which 309 completed follow-up. Baseline health status scores were 20.2 ± 7.3 (CAT), 2.9 ± 1.2 (CCQ) and 50.7 ± 17.3 (SGRQ). MCID estimates for improvement ranged − 3.1 to − 1.4 for CAT, − 0.6 to − 0.3 for CCQ, and − 10.3 to − 7.6 for SGRQ. Absolute higher – though not significant – MCIDs were observed for CAT and CCQ directly after PR. Significantly absolute lower MCID estimates were observed for CAT (difference − 1.4: CI -2.3 to − 0.5) and CCQ (difference − 0.2: CI -0.3 to −0.1) using a five-point GRC. Conclusions The recall period of a 15-point anchor question seemed to have limited impact on the MCID for improvement of CAT, CCQ and SGRQ during PR; although a 3-week MCID estimate directly after PR might lead to absolute higher values. However, the design of the anchor question was likely to influence the MCID of CAT and CCQ. Trial registration RIMTCORE trial #DRKS00004609 and #12107 (Ethik-Kommission der Bayerischen Landesärztekammer).

Study aimed to design and manufacture two biosensors, namely BIOS-I and BIOS-II, for 222Rn and Pb+2 measurements in building materials and soil samples. For comparison, the conventional detectors of RAD7 and CR-39 were used. The biosensor material used was based on ssDNA rich guanine or primer. The two biosensors have a difference in the sequence of the nitrogenous bases. The measurement revealed that the average of 222Rn exhalation by the BIOS-Ι was 373.30 Bqm-3, while the BIOS-ΙΙ was 342.29 Bqm-3. The average 222Rn exhalation measured by the CR-39 detector was 326.17 Bqm-3, whereas by the RAD7 detector it was 319.95 Bqm-3. This study found that 222Rn exhalation in the Indian and Chinese granites, soil, and Iraqi mosaic samples was higher than the limits recommended by WHO, while the rest of the samples were within the permissible limits. It is also known that there is a very weak positive correlation between BIOS-Ι or BIOS-ΙΙ and humidity, while a very weak negative correlation was found between them and temperature. There is a very strong positive correlation between radon exhalation recorded by RAD7 and humidity. On the other hand, there are no statistically significant differences between BIOS-I and BIOS-II at (level 0.01), while there are statistically significant differences between BIOS-I and CR-39 or RAD7 at level 0.01. It was concluded that the manufactured biosensors have better detection for radon than RAD 7 and CR-39 detectors.