Prevalence of Osteoporosis and Osteopenia: RESULTS
Characteristics of the 175 study participants are summarized in Table 2. Study participants had a mean age of 51 ± 13 years and were predominantly women (n=144, 82%). Patients had a mean RA disease duration of 14 ± 7 months and a substantial majority of participants (n=145, 83%) had received prior treatment with oral glucocorticoids (mean self-reported prednisone dose = 9.4 ± 9.2 mg/d). Patients had a mean body mass index of 31.3 ± 7.1 kg/m2 and approximately one-half of patients (n=99, 57%) were either current or past cigarette smokers. Many were receiving either calcium (n=82,47%) or vitamin D supplements (n=26, 15%) at the time of DXA measurement, but only a small minority had ever used prescription bisphospho-nate treatments (n=6, 3%). Overall, patients had moderate-to-severe disease activity as evidenced by mean tender and swollen joints counts in addition to mean disability index scores (Table 2).
Table 2. Osteoporosis disease risk factors and rheumatoid arthritis-related characteristics of study patients (n=175)
Mean ± SD
or frequency (%)
|Osteoporosis Risk Factors|
51 ± 13
|Body mass index, kg/m2||
|Ever glucocorticoid use||
|Ever use of bisphosphonate therapy 6 (3)|
|Rheumatoid arthritis-related characteristics|
|Disease duration, months||
14 ± 7
|Rheumatoid factor positivity||
|Tender joints (range 0-32)||
11.2 ± 11.4
|Swollen joints (range 0-32)||
5.5 ± 7.1
|HAQ disability index score (range 0-3)1!.59 ± 0.94|
|* Denominator as noted (n=175) with the exception of missing|
|data for menopausal (n=l) and smoking status (n=l); f HAQ:|
|Health Assessment Questionnaire11; % Based on physician|
|documentation at the time of study enrollment|
Site-Specific BMD Values and T Scores
Sex- and site-specific BMD values are summarized in Table 1. Although differences were not significant, BMD values for both lumbar spine (p=0.6) and femoral neck (p=0.3) were approximately 2-4% higher in men than in women. Using Caucasian reference data, the mean lumbar spine and femoral neck T scores were 0.29 (±1.65) SD and -0.14 (±1.28) SD, respectively. Corresponding T scores were -0.65 (±1.65) and -0.85 (±1.17) for the spine and femoral neck, respectively, when race/ethnicity-matched referent data were used.
Osteopenia and Osteoporosis Prevalence
Results of our primary analyses are summarized in Table 3. Using Caucasian referent data, approximately one-third of patients were classified as having osteopenia and/or osteoporosis (n=48, 32.9%), and eight patients (4.7%) were classified as having osteoporosis (treating and preventing osteoporosis). When African-American normative data were used instead, over one-half of patients were classified as having osteopenia or worse (n=94, 55.3%), and 15.9% (n=27) were classified to be osteoporotic.
Table 3. Site-specific frequency of osteopenia and osteoporosis in study patients based on peak normative reference data used to calculate T scores, number (%)
|Race/Ethnicity of Reference Data Used to Calculate T Score|
|Caucasian Reference Data||African-American Reference Data*|
|Femoral Neck1 Lumbar Spine||Femoral Neck||Lumbar Spine|
|131 (76%) 136 (79%) 37 (22%) 31 (18%) 4 (2%) 6 (3%)||91 (53%) 70 (41%) 11 (6%)||107 (62%) 41 (24%) 25 (14%)|
|* Disease classifications: healthy equivalent to T score > -1 standard deviation, osteopenia equivalent to T score <-l standard deviation and >-2.5 standard deviation, osteoporosis equivalent to T score <-2.5 standard deviation; f n=172 patients for femoral neck, n=173 for lumbar spine; t prevalence of osteoporosis higher for both lumbar spine (pO.001) and femoral neck (p=0.008) with the use of African-American reference data compared to the use of Caucasian reference data; prevalence of osteopenia and/or osteoporosis higher for lumbar spine (p<0.001) and femoral neck (p<0.001) with the use of ethnic-matched data.|
The overall prevalence of osteoporosis (is taken for the prevention or treatment of osteoporosis) increased significantly for both lumbar spine (p<0.001) and femoral neck (p=0.008) when race/ethnicity-matched referent data were used compared to the use of Caucasian normative data. Likewise, the prevalence of osteopenia and/or osteoporosis (T scores <-l SD) at the lumbar spine (p<0.001) and femoral neck (pO.OOl) was significantly greater with the use of race/ethnicity-matched normative data (Table 3).
Recognizing the current controversy in applying the World Health Organization’s criteria to men and premenopausal women, we restricted our analyses to postmenopausal women and obtained similar results (data not shown). Among postmenopausal women (n=88), four (4.6%) were classified to be osteoporotic at both the lumbar spine and femoral neck with the use of normative data from Caucasian women. With the use of race/ethnicity-adjusted T scores, the prevalence of osteoporosis (Canadian Didronel treats osteoporosis) at the spine (n=15, 17%) and femoral neck (n=8, 9%) for postmenopausal women was higher (p<0.05 for differences).