Table 2

One-step individual participant data meta-analysis, rate of moderate or severe COPD exacerbations: overall and by subgroup

N individuals (trials)Event rate per participant-year, control groupEvent rate per participant-year, intervention groupAdjusted incidence rate ratio (95% CI)*P valueP value for interaction
Overall469 (3)398/201.87 (1.97)381/205.66 (1.85)0.94 (0.78 to 1.13)0.52
Baseline 25(OH)D (nmol/L)
 <2587 (3)77/36.60 (2.10)51/41.52 (1.23)0.55 (0.36 to 0.84)0.0060.015
 ≥25382 (3)321/165.27 (1.94)330/164.13 (2.01)1.04 (0.85 to 1.27)0.71
GOLD spirometric grade
 1 or 2252 (3)139/109.17 (1.27)137/111.11 (1.23)1.01 (0.75 to 1.35)0.940.59
 3 or 4217 (3)259/92.70 (2.79)244/94.55 (2.58)0.91 (0.72 to 1.16)0.44
Concomitant inhaled corticosteroid at baseline
 No126 (3)63/49.94 (1.26)58/56.17 (1.03)0.93 (0.56 to 1.55)0.780.75
 Yes343 (3)335/151.93 (2.20)323/149.49 (2.16)0.96 (0.79 to 1.16)0.66
Body mass index (kg/m2)
 <25213 (3)210/103.67 (2.03)173/83.89 (2.06)1.03 (0.78 to 1.36)0.840.53
 ≥25256 (3)188/98.20 (1.91)208/121.77 (1.71)0.89 (0.70 to 1.15)0.38
Frequency of vitamin D dosing
 Intermittent bolus422 (2)374/189.75 (1.97)364/193.67 (1.88)0.96 (0.79 to 1.15)0.640.43
 Daily47 (1)24/12.12 (1.98)17/11.98 (1.42)0.74 (0.38 to 1.41)0.35
rs731236 (TaqI, VDR) genotype
 TT142 (2)105/57.09 (1.84)119/71.18 (1.67)0.95 (0.70 to 1.31)0.770.52
 CT198 (2)184/89.80 (2.05)163/89.20 (1.83)0.90 (0.67 to 1.19)0.45
 CC67 (2)65/37.75 (1.72)65/25.95 (2.51)1.28 (0.81 to 2.02)0.28
rs11568820 (cdx2, VDR) genotype
 GG234 (2)190/105.35 (1.80)196/104.79 (1.87)0.99 (0.77 to 1.28)0.950.72
 GA149 (2)151/67.80 (2.23)130/71.22 (1.83)0.92 (0.68 to 1.25)0.59
 AA20 (2)13/9.20 (1.41)12/7.86 (1.53)1.41 (0.55 to 3.66)0.48
rs7041 (HaeIII, DBP) genotype
 GG106 (2)108/48.67 (2.22)106/47.72 (2.22)1.08 (0.78 to 1.49)0.660.15
 GT207 (2)157/88.47 (1.77)182/99.11 (1.84)1.05 (0.78 to 1.40)0.77
 TT92 (2)89/46.18 (1.93)63/38.92 (1.62)0.75 (0.51 to 1.09)0.14
rs4588 (StyI, DBP) genotype
 CC191 (2)175/91.53 (1.91)168/83.16 (2.02)1.05 (0.80 to 1.39)0.720.34
 CA184 (2)151/77.08 (1.96)158/90.00 (1.76)0.93 (0.70 to 1.24)0.61
 AA35 (2)31/16.95 (1.83)25/14.45 (1.73)0.84 (0.41 to 1.73)0.64
Gc (DBP) genotype
 Gc1/1187 (2)172/89.45 (1.92)164/81.14 (2.02)1.07 (0.80 to 1.42)0.650.24
 Gc2/1183 (2)151/77.08 (1.96)158/89.16 (1.77)0.93 (0.70 to 1.24)0.63
 Gc2/232 (2)31/16.78 (1.85)18/12.62 (1.43)0.68 (0.29 to 1.58)0.37
  • GOLD spirometric grade 1 or 2: FEV1 ≥50% predicted; grade 3 or 4: FEV1 <50% predicted. *, adjusted for age, sex, COPD severity and trial.

  • 25(OH)D, 25-hydroxyvitamin D; DBP, vitamin D binding protein; Gc, group-specific component; GOLD, Global Initiative for Chronic Obstructive Lung Disease; VDR, vitamin D receptor.