In general, we found that the utilization of health services and prescription patterns among SLE patients followed by primary care physicians and rheumatologists in Puerto Rico were similar. The only differences found were that rheumatologists ordered SLE biomarkers of disease activity and prescribed hydroxychloroquine more frequently than did primary care physicians. Office and emergency room visits, hospitalizations, use of routine laboratory tests, and prescriptions for SLE drugs except for hydroxychloroquine were comparable for both groups.
The American College of Rheumatology Ad Hoc Committee on SLE guidelines recommends that primary care physicians should refer SLE patients to rheumatologists to establish SLE diagnosis; assess disease activity and severity; establish general management; and manage uncontrolled disease, major organ damage, and complications of therapy.4
Other study suggests that even patients with mild disease should have at least concurrent care with rheumatologists, since most of these patients will eventually require rheumatologic interventions.6
These guidelines seem to be followed in Puerto Rico. Seventy-six percent of the 877 SLE patients were followed exclusively by rheumatologists, 14% of patients were followed by both rheumatologists and primary care physicians, and only 10% were seen only by primary care physicians. These data suggest that rheumatologists are the main healthcare providers for SLE patients in Puerto Rico.
We observed that osteopenia/osteoporosis was diagnosed more commonly in lupus patients followed by rheumatologists than by primary care physicians. The most likely explanation for this observation is that rheumatologists ordered bone mineral density measurements more frequently for screening and preventing glucocorticoid-induced osteoporosis. This possibility is in agreement with the findings of Curtis et al, who found that patients seen by rheumatologists had higher rates of bone density measurements and treatment for osteoporosis than did patients followed by family physicians.7
Unfortunately, we did not examine bone density measurements in our population. It is unlikely, however, that the differences observed here in osteopenia/osteoporosis could be related to glucocorticoid treatment because the use of this drug was similar for both groups.
ESR, anti-dsDNA antibodies, and serum complements were ordered more frequently by rheumatologists than by primary care physicians. ESR elevation and elevated anti-dsDNA antibodies are strongly associated with disease activity and damage accrual in SLE and therefore should be used to monitor lupus patients8
. Few studies have examined the use of laboratory tests in the clinical practice of rheumatologists.9
In contrast to our study, Donald and Ward found that most (92%) rheumatologists in the United States use anti-dsDNA antibodies and C3 levels, but not ESR, to monitor SLE patienis9
. In our study, rheumatologists more frequently ordered ESR (72%) than anti-dsDNA (32%) antibodies and serum complements (46%).
We observed that rheumatologists more frequently prescribed hydroxychloroquine than did primary care physicians. Likewise, Zink et al found that rheumatologists prescribed antimalarials in 36.5% of SLE patients versus the 17.0% by nonrheumatologists.10
However, in comparison to other studies, rheumatologists in Puerto Rico prescribe hydroxychloroquine relatively less frequently.10–13
The utilization rates of hydroxychloroquine in lupus patients range from 36% to 67%.10–14
Generally, hydroxychloroquine is usually used for lupus patients with mild disease.15,16
In addition, this antimalarial drug has several other clinical benefits for lupus patients. 11–13, 16–19
Hydroxychloroquine decreases major disease flares, reduces the risk of damage accrual, decreases serum cholesterol levels, decreases the risk of thromboric events, protects against osteoporosis in patients treated with glucorticoids, and reduces mean glucose levels in patients with lupus. 11–13, 16–19
Therefore, hydroxychloroquine is recommended for all lupus patients, regardless of disease activity or severity.
The present study has some limitations. First, the diagnosis of SLE was based only on the ICD-9 code, and not on American College of Rheumatology classification criteria. Second, we only included SLE patients with private health insurance but not those under the government healthcare program, most of whom are below the poverty level. Several studies have shown that lower socioeconomic level is related to higher morbidity and mortality in SLE.2,20
Thus, it would be very important to examine healthcare utilization and use of pharmacologic agents in this population of patients. Third, since the data were collected for one particular year, we do not know if patients seen by primary care physicians were previously evaluated by rheumatologists and guidelines regarding general management and treatment were already given. Finally, we could not determine the length of time since SLE diagnosis. Variability in disease duration could account for some differences in services and drug utilization between patients followed by the two types of providers.
Despite these limitations, the results presented here have clinical implications. Also, it highlights the importance to access a large database from a health insurance company in order to identify those areas in healthcare delivery that need attention or improvement. This study suggests that primary care physicians should be more aware of ordering bone mineral density measurements, particularly for lupus patients taking glucocorticoids. Furthermore, it shows the importance for both rheumatologists and primary care physicians to consider the use of hydroxychloroquine more frequently in their lupus patients. Finally, primary care physicians are advised to use ESR and anti-dsDNA antibodies more often to monitor disease activity in SLE patients.
Implications for Improving Health Disparities
Optimal utilization of hydroxychloroquine in lupus patients could result in a better disease course and outcome as the use of this immunomodulatory agent has been associated with lower disease activity and damage accrual in SLE11–13, 16–19
Similarly, a better use of SLE disease activity biomarkers might help to identify those patients at risk of disease flares and, hence, aid in providing prompt and effective immunosuppressive therapy.