Up tp now, disease activity of COPD patients in their home environment has usually been recorded by questionnaires (e.g. COPD assessment test). Digital multifactorial measurements, via the "mobile COPD Status test" app, offer a new way of displaying disease activity. However, there is no independent study that has examined whether digitally collected parameters correlate with the common used measurement instruments for COPD patients (both in cross-sectional and longitudinal course).

The aim of this exploratory study is to investigate the correlation between the mobile COPD Status test (mCST App, KAIA Health) and a conventional collected clinical data set of routine measurements as well as the subjective symptoms and activity perception of COPD patients in their home environment, with and without exacerbation.

In total 130 COPD patients will be included prospectively in this multicenter trial during an inpatient pulmonary rehabilitation program at the Schoen Klinik Berchtesgadener Land, Schönau am Koenigssee, (Germany) or during a stay (inpatient or outpatient) at the Klinikum Nuremberg (Germany).

In general, the study is divided into two parts - study part I, within the duration of the pulmonary rehabilitation program/ hospital stay and study part II, in the home environment (24 weeks).

Study part I:

Visit 1 (day 0, in the clinic) + Visit 2* (day 14+/-5, in the clinic/outpatient)

Each study participant is given a smartphone. Under the guidance of study personnel, data collection of the following parameters is carried out via KAIA mCST App):

• four standardized questions regarding coughing frequency, expectoration, chest tightness and shortness of breath during exercise
• Dyspnea at rest
• Breath sounds via microphone
• Inspiration/expiration length via microphone
• Respiratory rate via smartphone measurements
• Physical performance via the sit-to-stand test (1min) with counting the repetitions and checking the correct execution via smartphone camera
• Gait analysis (2x 10 steps walking) via acceleration sensors of the smartphone or via motion tracking by camera during defined gait measurements.

The mCST app takes about 15 minutes to complete.

Additionally, clinical routine data will be collected:

• medical history
• body plethysmography & blood gases
• EKG
• health related quality of life
• dyspnea
• 6-minute walk distance
• 1-minute-sit to stand test

Study part II:

Visits 3 to 26 (week 3 to 26, in participants home environment) From study visit 3 on, participants are observed weekly in their home environment for a total of 24 weeks. No further clinic visits take place. Disease activity is measured weekly as patient reported outcomes using the mCST app (for details see description of visit 1/2, part 1). In addition to the weekly mCST app, patients are invited to fill out daily a symptom diary before going to bed. The symptom diary contains the EXACT questionnaire and an activity questionnaire.

*Visit 2 is optional

Inclusion Criteria:

• hospitalisation at Schoen Klinik Berchtesgadener Land or Klinikum Nuremberg
• Chronic obstructive pulmonary disease GOLD A-D
• sufficient german language and samrtphone skills to understand the mCST app
• sufficient good WLAN Connection in the domestic environment

Exclusion Criteria:

• presence of comorbidities which could interfere the course of the trial (e.g. cognitive deficits, neurological or orthopedic diseases)
• significant mental illness, legal incapacity or limited legal capacity
• patients who are unable or unwilling to perform the study activities acording to the protocol

COPD patients