Impact of vitamin D on spirometry findings and quality of life in patients with chronic obstructive pulmonary disease: a randomized, double-blinded, placebo-controlled clinical trial

Figures & data

Figure 1 Study flowchart (CONSORT format).

Table 1 Studied variables before intervention in both control and vitamin D groups

	Variables	Group		P-value
		Intervention (vitamin D3)	Control (placebo)
The beginning of the study	Age (years)	67.9±7.9	68.4±7.8	0.748*
	Sex (male)	30 (93.8%)	30 (96.8%)	0.573**
	BMI (kg/m^2)	24.33±2.13	24.55±1.94	0.665*
	Cigarette smoking (per year) (mean ± SD)	32±14	31±13	0.866*
	FEV1 (mean ± SD)	57.98±17.67	57.7±17.99	0.949*
	FEV1/FVC (mean ± SD)	56.75±12	58.76±9.82	0.472*
	Exacerbations, n (%)	10 (31.3%)	11 (35.5%)	0.722***
	Exacerbations (mean ± SD)	0.53±0.98	0.55±0.85	0.658****
	CAT score (mean ± SD)	15.3±7.35	15.48±9.32	0.767****
	COPD severity, n (%)	6 (18.8%)	9 (29%)	0.294**
		16 (50%)	9 (29%)
		5 (15.6%)	9 (29%)
		5 (15.6%)	4 (12.9%)
	25-Hydroxyvitamin D3 levels, ng/mL, (mean ± SD)	19.33±5.18	18.55±4.58	0.528*

Notes: *t-test; **Fisher’s exact test, ***Chi squre; ****Mann–whitney.

Abbreviations: BMI, body mass index; CAT score, COPD assessment test score; FEV1, Forced expiratory volume at first second; FVC, Forced vital capacity.

Table 2 Studied variables at 2 and 6 months after intervention in both control and vitamin D groups

			Intervention (vitamin D3)	Control (placebo)	P-value
After 2 months	FEV1 (mean ± SD)		58.69±17.68	57.87±18.06	0.857*
	FEV1/FVC (mean ± SD)		57.43±12.09	58.9±9.56	0.593*
	Exacerbations, n (%)		3 (9.4%)	3 (9.7%)	>0.999**
	Exacerbations (mean ± SD)		0.09±0.3	0.1±0.3	0.968****
	CAT score		14.25±7.43	15.29±9.53	0.842****
	COPD severity, n (%)	A	6 (18.8%)	6 (19.4%)	0.665**
		B	15 (46.9%)	14 (45.2%)
		C	3 (9.4%)	6 (19.4%)
		D	8 (25%)	5 (16.1%)
After 6 months	FEV1 (mean ± SD)		58.93±17.73	58.18±17.91	0.868*
	FEV1/FVC (mean ± SD)		57.74±11.86	59.2±9.99	0.6*
	Exacerbations, n (%)		4 (12.5%)	8 (25.8%)	0.179***
	Exacerbations (mean ± SD)		0.16±0.45	0.32±0.6	0.184****
	CAT score (mean ± SD)		13±7.47	15.65±9.46	0.250****
	COPD severity	A	6 (18.8%)	6 (19.4%)	0.979***
		B	14 (43.8%)	13 (41.9%)
		C	5 (15.6%)	6 (19.4%)
		D	7 (21.9%)	6 (19.4%)
	25-hydroxyvitaminD3 levels (mean ± SD), ng/mL		51.83±7.93	19.43±5.22	<0.001*

Notes: *Student's t-test; **Fisher’s exact test; ***χ2; ****Mann–Whitney U test.

Abbreviation: CAT, COPD Assessment Test.

Table 3 Mean differences in studied variables in both control and vitamin D groups

Variables	Duration	Group	Mean ± SD	P-value
FEV1	After 2 months from baseline	Intervention	0.7±1.11	0.073*
		Control	0.18±1.19
	Between 2 and 6 months from baseline	Intervention	0.25±0.74	0.820*
		Control	0.31±1.44
	After 6 months from baseline	Intervention	0.95±1.88	0.089*
		Control	0.49±1.22
FEV1/FVC	After 2 months from baseline	Intervention	0.67±1.27	0.116*
		Control	0.15±1.35
	Between 2 and 6 months from baseline	Intervention	0.32±1.03	0.944*
		Control	0.3±1.17
	After 6 months from baseline	Intervention	0.99±1.28	0.640**
		Control	0.45±1.51
Exacerbations	After 2months from baseline	Intervention	−0.44±1.01	0.431**
		Control	−0.45±0.77
	Between 2 and 6 months from baseline	Intervention	0.06±0.5	0.129**
		Control	0.23±0.5
	After 6 months from baseline	Intervention	−0.38±0.83	0.613**
		Control	−0.23±0.72
CAT score	After 2 months from baseline	Intervention	−1.09±1.03	0.001**
		Control	0.19±1.01
	Between 2 and 6 months from baseline	Intervention	−1.25±1.63	<0.001**
		Control	0.35±1.02
	After 6 months from baseline	Intervention	−2.34±1.41	<0.001**
		Control	0.16±1.04

Notes: *Student's t-test; **Mann–Whitney U test.

Abbreviation: CAT, COPD Assessment Test.