Influence of Anti-TNF and Disease Modifying Antirheumatic Drugs Therapy on Pulmonary Forced Vital Capacity Associated to Ankylosing Spondylitis: A 2-Year Follow-Up Observational Study

Table 3

Primary outcomes. Comparison in absolute changes on pulmonary function tests between baseline and 24 months in DMARDs group versus anti-TNF+DMARDs group.

Variable	DMARDs			Anti-TNF + DMARDs			Comparison between groups at 24 months; (Δ absolute change)
	Baseline	24 months	Absolute change	Baseline	24 months	Absolute change
FVC %, median (ranges)	69 (52–79)	80 (70–82)	11 (2–18)	69 (57–77)	82 (79–83)	13 (5–23)	0.04
FEV1%, median (ranges)	82 (80–90)	86 (82–95)	3 (−2–8)	82 (81–85)	85 (81–90)	3 (−4–6)	0.60
Ratio FEV1/FVC, median (ranges)	94.5 (87–112)	97 (90–107)	2 (−15-14)	84 (82–99)	90 (86–99)	4 (0–13)	0.03
Patients with improvement	% achieving improvement					% achieving improvement	Comparison of % achieving improvement
Restrictive pattern, (%)	20 (100)	9 (45)	11 (55.0)	16 (100)	2 (12.5)	14 (87.5)	0.04
Changes of cut-off point in FVC%
Normal (≥80%), (%)	0	11 (55.0)	—	0	14 (87.5)	—	<0.001
FVC% 70–79%, (%)	9 (45.0)	7 (35.0)	—	8 (50.0)	2 (12.5)	—
FVC% 50–69%, (%)	7 (35.0)	2 (10.0)	—	2 (12.5)	0	—
FVC% 50%, (%)	4 (20.0)	0	—	6 (37.5)	0	—

DMARDs, disease modifying antirheumatic drugs; anti-TNF + DMARDs, antitumor necrosis factor + DMARDs; FVC%, forced vital capacity; FEV₁%, forced expiratory volume in 1 second. Quantitative variables are shown as median and ranges; qualitative variables are shown in frequencies (%). Absolute change is obtained from the differences at 24 months versus baseline. values for Δ absolute change: comparison between groups of differences in absolute changes at baseline and 24 months. Comparison of the absolute change between groups at 24 month was performed with Mann-Whitney test. Fisher exact test was used to compare the proportion of patients who achieve changes of the cut-off point in FVC%.