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Table 1 Patient characteristics in the different datasets

From: Primary data, claims data, and linked data in observational research: the case of COPD in Germany

 

Primary dataset

N = 636

Primary dataset patients not linked

N = 100

Linked dataset

N = 536

Claims dataset

N = 74,916

Based on primary data

Based on primary data

Based on primary data

Based on claims data

Based on claims data

Age, years

 Mean (SD)

68.1 (10.1)

68.6 (11.0)

68.0 (9.9)

68.5a (9.9)

70.9 (11.7)

 Median (IQR)

69 (15)

70 (16)

69 (15)

69 (14)

73 (18)

Female gender, n (%)

242 (38.1)

47 (47.0)

195 (36.4)

195 (36.4)

34,448 (46.0)

Smoking, n (%)

     

Smoker

218 (34.3)

32 (32.0)

186 (34.7)

247 (46.1)

16,076 (21.5)

Former smoker

400 (62.9)

67 (67.0)

333 (62.1)

  

Non-smoker

17 (2.7)

1 (1.0)

16 (3.0)

  

Not-specified

1 (0.2)

0 (0.0)

1 (0.2)

  

Comorbidities, n (%)b

Hypertension

287 (45.1)

44 (44.0)

243 (45.3)

450 (84.0)

59,153 (79.0)

Diabetes (Type 1 or 2)

143 (22.5)

24 (24.0)

119 (22.2)

189 (35.3)

27,905 (37.2)

Depression

48 (7.6)

12 (12.0)

36 (6.7)

157 (29.3)

17,647 (23.6)

Osteoporosis

50 (7.9)

7 (7.0)

43 (8.0)

99 (18.5)

12,364 (16.5)

FEV1, Lc

Mean (SD)

1.50 (0.6)

1.56 (0.7)

1.50 (0.6)

NA

NA

Median (IQR)

1.4 (0.8)

1.4 (0.9)

1.4 (0.8)

  

% of predicted FEV1d

Mean (SD)

55.6 (17.4)

57.2 (18.2)

55.3 (17.2)

NA

NA

Median (IQR)

57.0 (25.3)

60.0 (26.4)

56.0 (25.8)

  
  1. COPD chronic obstructive pulmonary disease, FEV1 forced expiratory volume in 1 s, ICD-10, International Classification of Disease, 10th Edition, IQR interquartile range, SD standard deviation
  2. Primary dataset: all data reported for index date except comorbidities (any known to study physician). Claims dataset: all data reported for date of first COPD diagnosis except comorbidities (from January 2010 to date of first COPD diagnosis). Linked dataset: all data reported for linked dataset index date except comorbidities (primary: any known to study physician; claims: from January 2010 to linked dataset index date)
  3. Smoking status was identified in the claims data using ICD-10 code F17. Comorbidities were selected based on those most commonly reported which could be directly compared between primary and claims data using ICD-10 codes: diabetes: E10/E11; depression: F32/F33; osteoporosis: M80-M82; hypertension: I10-I15
  4. aIn the claims data, only birth year was available. Therefore, age at linked dataset index date was calculated based on the assumption that all patients were born on July 1 of the respective year
  5. bValues were calculated for all patients for whom data were available (primary sample/linked sample): diabetes: 621/518; depression: 611/515; osteoporosis: 561/477; hypertension: 600/512
  6. cValues were calculated for all patients for whom data were available (primary sample: n = 620; linked sample: n = 527)
  7. dValues were calculated for all patients for whom data were available (primary sample: n = 612; linked sample: n = 522)
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Respiratory Research

ISSN: 1465-993X

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