Table 1 Summary of information from studies used in the review

REPEATABILITY: 2 successive PD₁₅ measurements under same conditions, no interventions

ND

 Barben et al. (2003) [17]

17

 ≤ 635

N/A

2–7 days

1.050

(0.941–1.172)

0.071

0.673

 Udesen et al. (2017)^† [18]

41

No

N/A

6 months

1.225

(0.907–1.652)

0.292

0.598

CROSSOVER: 2 treatments, one post-treatment PD₁₅ measurement for each treatment

 Brannan et al. (2000) [19]

24

 < 350

Nedocromil/

Placebo

Single dose

2.625

(1.893–3.641)

1.392

0.791

 Brannan et al. (2001) [20]

20

 < 290

Fexofenadine/

Placebo

Single dose

2.696

(1.713–4.242)

1.431

0.988

19

 < 290

Montelukast/

Placebo

Single dose

0.825

(0.653–1.043)

− 0.278

0.496

CROSSOVER: 2 treatments, pre and post PD₁₅ measurements for each treatment

 Anderson et al. (2012)^‡ [21]

21

No

FP 500 mg/

FP 100 mg

2 weeks

1.4

(0.7–3.1)

0.5^‡

1.2^‡

 Clearie et al. (2012) [22]

13

 ≤ 635

FP + SM/

FP (smokers)

2 weeks

1.5

0.6

1

11

 ≤ 635

FP + SM/

FP (non-smokers)

2

1

0.9

 Brannan et al. (2015) [23]

23

 ≤ 315

Fish oil/

placebo

3 weeks

0.76

(0.43 –1.32)

− 0.402

0.94

PARALLEL GROUP: 2 or more treatment groups, pre- and post-treatment PD₁₅ measurements

 Barakat et al. (2012) [24]

11

 ≤ 635

FP 100 mg

7 weeks

N/A

N/A

1.3

1.61

11

FP 500 mg

0.62

(0.21–1.78)

− 0.7

1.0

 Toennesen et al. (2018)^† [25]

34

No

Control

(no treatment)

8 weeks

N/A

N/A

0.87

1.36

29

Exercise

0.81

(0.71–0.92)

0.30

1.15

33

Diet

0.92

(0.81–1.05)

− 0.12

0.88

29

Exercise + diet

0.91

(0.78–1.05)

− 0.14

0.90

SINGLE GROUP: Comparing change in PD₁₅ pre- to post-treatment

 Brannan et al. (2002) [26]

18

Yes

 ≤ 635

Budesonide

6–9 weeks

3.73

(2.87–4.86)

1.90

0.52

0.74

 Koskela et al. (2003)^§ [27]

17

Yes

 ≤ 635

Budesonide

6 months

3.6

(1.6–8.4)

1.85

1.7

2.4

 Kersten et al. (2011) [28]

17

No

Dropping of LABA

30 days

0.92

(0.64–1.32)

− 0.13

0.73

1.03