Predictors of Osteoporosis and Vertebral Fractures in Patients Presenting with Moderate-to-Severe Chronic Obstructive Lung Disease

Figures & data

Table 1.  Characteristics of the 85 study participants

Men	78 (92)
Age, years
< 65	10 (12)
65–74	31 (36)
≥ 75	44 (52)
Body mass index
< 18.5	10 (12)
18.5–24.9	61 (72)
≥ 25.0	14 (16)
Current smoker	10 (12)
> 60 g/day alcohol consumption	8 (9)
Medical history
Rheumatoid arthritis	3 (4)
Fractures	29 (34)
Parental hip fracture	7 (8)
Drug therapy
Corticosteroids	9 (11)
Orala
Inhaledb, μg/day
0	44 (53)
200–799	19 (23)
≥ 800	20 (24)
Warfarinb	14 (16)
Oral corticosteroidsa or warfarinb	22 (26)
Years of oxygen therapy
< 2	12 (14)
≥ 2	13 (15)
Pulmonary function tests,%predicted
Vital capacity
≥ 90	42 (49)
80–89	16 (19)
< 80	27 (32)
Forced expiratory volume in 1 sec
≥ 50	27 (32)
30–49	45 (53)
< 30	13 (15)
DLCO/VA,c
≥ 50	16 (24)
30–49	28 (42)
< 30	23 (34)

Values are numbers (%) of observations.

^aCurrent or previous use, b current use, c n = 67 measurements

DLCO/VA: diffusing capacity of carbon monoxide per liter alveolar volume

Table 2.  Factors correlated with osteoporosis and vertebral fractures by single variable logistic regression analysis

	A. Osteoporosis		B. Vertebral fracture
	Odds ratio [95% CI]	P	Odds ratio [95% CI]	P
Female gender	27.40 [3.05–26]	0.003	1.41 [0.29–6.80]	ns
Age ≥75 years	2.03 [0.72–5.76]	ns	2.68 [1.05–6.86]	0.04
Body mass index
< 18.5	9.53 [2.14–42.40]	0.003	1.18 [0.30–4.64]	ns
18.5–25	1.00	-	1.00	-
> 25	0.31 [0.03–2.64]	ns	0.71 [0.20–2.53]	ns
Dyspnea scale ≥2	3.20 [1.01–10.2]	0.04	0.69 [0.47–3.13]	ns
Oral corticosteroids a	0.91 [0.17–4.75]	ns	3.62 [0.80–16.5]	0.09
Inhaled corticosteroids b, μg/day
0	1.00	-	1.00	-
200–600	0.73 [0.17–3.06]	ns	0.42 [0.16–2.13]	ns
≥ 800	2.59 [0.81–8.24]	ns	2.30 [0.76–6.94]	ns
Treatment with warfarin b	0.84 [0.21–3.47]	ns	2.98 [0.92–9.68]	0.06
Treatment with oral corticosteroids a or warfarin b	0.94 [0.30–2.99]	ns	4.57 [1.60–13.1]	0.004
Years of oxygen therapy
none	1.00	-	1.00	-
< 2	1.49 [0.34–6.40]	ns	1.38 [0.36–5.33]	ns
≥ 2	3.82 [1.07–13.6]	0.03	3.86 [1.10–13.50]	0.03
Vital capacity (% predicted)
≥ 90	1.00	-	1.00	-
80–90	1.05 [0.18–6.09]	ns	1.80 [0.52–6.22]	ns
< 80	6.87 [2.06–22.8]	0.001	3.00 [1.05–8.58]	0.04
Forced expiratory volume in 1 sec (% predicted)
≥ 50	1.00	-	1.00	-
30–50	1.10 [0.32–3.70]	ns	1.27 [0.43–3.71]	ns
< 30	3.77 [0.88–16.2]	0.07	5.02 [1.24–23.8]	0.02
Carbon monoxide diffusing capacity/liter alveolar volume (% predicted)
≥ 50	1.00	-	1.00	-
30–50	1.17 [0.19–7.20]	ns	0.93 [0.24–3.54]	ns
< 30	5.39 [0.99–29.3]	0.05	1.35 [0.34–5.36]	ns
Emphysema score	2.71 [1.35–5.48]	0.005	0.90 [0.58–1.40]	ns
Serum concentrations
Uncarboxylated osteocalcin > 4.5 ng/ml	2.64 [0.94–7.48]	0.06	2.02 [0.77–5.32]	ns
Bone alkaline phosphatase > 29.0 U/l	4.00 [1.11–14.3]	0.03	1.49 [0.42–5.24]	ns
Urinary NTX > 54.3 nmol BCE/mmol creatinine	6.11 [1.52–24.6]	0.01	1.25 [0.32–4.87]	ns
T score
≥ -1	-	-	1.00	-
< -1 and ≥ -2.5	-	-	1.25 [0.41–3.78]	ns
< -2.5	-	-	3.39 [0.95–12.00]	0.06

^aCurrent or previous use; bcurrent use; CI = confidence interval; NTX = N-telopeptide of type 1 collagen; BCE = bone collagen equivalent.

Table 3.  Independent predictors of osteoporosis and vertebral fracture by multiple variable logistic regression analysis

A. Osteoporosis	Odds ratio [95% CI]	P
Female gender	17.2 [1.35–219]	0.02
Body mass index < 18.5	7.41 [0.98–56.1]	0.05
Vital capacity < 80%	6.68 [1.66–26.8]	0.007
Serum bone alkaline phosphatase > 29.0 U/l	7.64 [1.51–38.6]	0.01
B. Vertebral fracture(s)	Odds ratio [95% CI]	P
Age ≥ 75 years	2.93 [1.01–8.47]	0.04
Treatment with oral corticosteroidsa or warfarinb	6.00 [1.89–19.0]	0.002
Forced expiratory volume in 1 sec < 30%	7.52 [1.77–32.0]	0.006
C. Multiple vertebral fractures	Odds ratio [95% CI]	P
Treatment with oral corticosteroidsa or warfarinb	11.4 [1.92–67.6]	0.007
Forced expiratory volume in 1 sec < 30%	8.24 [1.23–55.5]	0.03
LTOT ≥ 2 years	4.74 [0.82–27.5]	0.08

^aCurrent or previous use; bcurrent use, CI = confidence interval; LTOT = long-term oxygen therapy.

Figure 1.  Relationship between a) the 10-year probability of major osteoporosis-related fractures calculated with the FRAX algorithm; and, b) the number of vertebral fractures detected in our study population. All between-groups differences are statistically non-significant.