This study examined the screening, prophylaxis, and treatment of osteoporosis in a large, community-based cohort of patients with physician-confirmed SLE. Regardless of whether we used lenient or strict definitions to delineate the patient populations eligible for relevant processes of care, the proportion of patients receiving these interventions was similar. Screening for osteoporosis with a BMD test occurred more frequently (69–74%) than calcium and vitamin D use (56–58%), or antiresorptive or anabolic use (54–56%), even when the QI III (Treatment) analysis was restricted to men and post-menopausal women (54–57%). We conclude that osteoporosis screening, prophylaxis, and treatment for SLE patients is suboptimal.
Our results show slightly higher proportions of patients receiving bone health-related care compared with prior estimates. Lee et al. surveyed US women with SLE seen in an academic rheumatology practice. In that study of 204 women, 50% reported calcium use and approximately 45% reported vitamin D use; 62% were post-menopausal, and 50% were currently using glucocorticoids. 32
In our sample, with a comparable fraction of post-menopausal women and patients on glucocorticoids, 62% of patients reported calcium use and 55% reported vitamin D use. Almehed et al. studied 163 women with SLE in Sweden, again with similar fractions of post-menopausal patients and steroid users: 53% of these patients reported taking calcium and vitamin D.4
Only 35% of patients with documented osteoporosis were taking bisphosphonates. In our sample, 47% of patients with documented osteoporosis were taking antiresorptive or anabolic agents. Pineau et al. examined a clinical database to show that that 40% of female SLE patients from the University of Toronto Lupus Clinic received a BMD test over a 5 year period. 33
Our sample showed that 51% of patients reported receiving a BMD test within 2 years. Self-reported use of DXA scans has been shown to have a very high positive predictive value when compared with medical chart review.34
One possible explanation for these discrepancies is that over time, awareness of osteoporosis has increased, and patients and their physicians are taking more care to perform screening, prevention, and treatment. Alternately, these differences may be a result of dissimilarities in health care system factors or the demographics of the populations studied.
We found that the major predictors of receipt of care varied by quality indicator and by denominator. Important factors predicting higher quality care included female sex, older age, Caucasian race, and longer disease duration, although these were not predictive for the receipt of all QIs. Notably, in the model that examined the FORMAL denominator, the only predictive factors were older age (QI I (Screening) only) and Caucasian race (QI II (Calcium and Vitamin D) only).
Our findings regarding predictors of care are not surprising: post-menopausal women without SLE have an indication for BMD testing and osteoporosis prophylaxis.35
In addition, our results are consistent with previous studies: Pineau et al. report that SLE patients who were referred for BMD testing had a greater number of traditional risk factors for osteoporosis, higher SLE activity, renal involvement, increased damage, higher mean glucocorticoid dose, increased use of immunosuppressants, and presence of avascular necrosis.33
In studies of osteoporosis care in patients with rheumatoid arthritis (RA), predictors have been similar. Aizer et al. assessed predictors of BMD testing among 2717 RA patients entering the CORRONA database without a prior dual energyX-ray absorptiometry (DXA) scan: older age, female sex, history of fracture, and history of steroid use predicted BMD testing within 12 months of entering the study.36
Solomon et al. evaluated osteoporosis care in 236 RA patients taking oral glucocorticoids: rates of BMD testing were low (23%), as were calcium and vitamin D use (42%). 37
Predictors of care included female sex, post-menopausal status, and having no additional comorbidities. Although these studies did not find as association of racial/ethnic groups with quality care, studies of quality indicators for cardiovascular disease, stroke and TIA, and diabetes have found such racial disparities.38,39
The fact that we found few predictors of care may indicate that we were limited in our power to detect differences; however, it is important to note that receipt of the QIs was low overall.
Our results must be interpreted with several caveats. First, data for the LOS, including data used for definitions of the numerators and denominators for the quality indicators, were collected by self-report. There is support in the literature for the validity of self-report for fragility fractures and osteoporosis diagnoses, as well as for BMD testing and medication use, including calcium and vitamin D: The sensitivity and specificity of self-report for documented hip fracture has been found to be very high.40,41
Agreement between self-report and medical record for the diagnosis of osteoporosis appears to be lower, but “false positive” self-reported diagnoses of osteoporosis arerare.42
Self-reported use of DXA scans has a 93% positive predictive value for DXA documented in the medical record. 34
The concordance of self-report for medication use (including calcium and vitamin D use) with medical record or administrative claims data is variable.43,44,45
However, several studies have shown substantial agreement between patient interview and medical records as sources of information regarding medication use and suggest that the impact of possible misclassification on models that predict medication use is minimal.,46,47
Overall, these studies show that the validity self-report for bone-health related care is reasonable, and therefore our results are likely reliable.
Second, few (127) patients met criteria for the formal QI denominators. We may have been underpowered to detect differences in rates of QI receipt among different subgroups of patients in this group. Third, quality indicators are process measures designed to be assessed on physicians or health-care systems and are intended to account for patient refusal of a measure or contraindications to a drug. We do not have information on reasons for drug non-use or contraindications (other than pre-menopausal status) available in this study, so it is possible that some patients were intolerant or otherwise ineligible to take calcium, vitamin D, or antiresorptives/anabolics. In this case, we may be underestimating the proportion of patients receiving care consistent with the quality indicators.
Based on the low receipt of the 3 bone-health-related SLE quality indicators, we have established that there exists a gap between actual and minimally-acceptable care. Quality-improvement efforts should address osteoporosis prevention and treatment among all SLE patients, especially in those taking high-dose, prolonged steroids. Educational initiatives highlighting the SLE quality indicators to SLE patients and their providers will likely improve the rates of quality bone health-related care in these populations.