To our knowledge this is the first report to examine the impact of SUD on screening for osteoporosis and the frequency of osteoporosis diagnosis in women with schizophrenia and other psychotic disorders. Osteoporosis screening and treatment is essential as bone fracture is a significant clinical and economic concern. Twenty percent of people in the US sustaining an osteoporotic hip fracture die within 1 year, another 20% become permanently disabled, and 50% can no longer walk without assistance after the event (11
). These associated costs of osteoporosis-related fractures and repair are estimated to cost 17 billion dollars in the US alone (25
Overall, we found a low rate of osteoporosis screening in the Medicaid population as a whole. Just 4% of our Medicaid sample of women aged 50 years and older without any record of osteoporosis received osteoporosis screening within a one-year period. It should be noted that such screening is not necessarily indicated for all women who are peri- or even post-menopausal. Instead the clinical focus for such screening is placed upon women with various risk factors especially including atraumatic fractures, but others such as smoking or the presence of diabetes (26
). From our administrative data, we could not accurately define the subset of women who had these clinical indicators. Many people do not begin screening until the age of 60 or 65; however, people with severe mental illness or substance abuse have many risk factors that indicate earlier screening age targets (11
). In one study of women over the age of 66 years, population screening rates were reported on the order of 9 to 20% (depending upon Medicaid or Medicare engagement, and the presence or absence of diabetes) (27
). Such population screening rates seem consistent with the observations in our study given the fact that our population is younger and thus less likely to require or be referred for screening, and additionally given the fact that the rates for the study just cited were based on a 2-year follow-up whereas ours were based on a single year follow-up.
In this study we found that, in the absence of substance use disorder, rates of screening for osteoporosis were comparable among women with schizophrenia and other psychosis, women with major mood disorders, and the control population (). One small study (N=46 schizophrenia and N=46 controls) in a VA population aged 45–64 found similar rates of screening in the two groups, but that people with schizophrenia had significantly lower rates than controls of medication prescription for prevention and treatment of osteoporosis (28
). In our study, people with SUD in the absence of other major psychiatric conditions had a 39% lower likelihood of receiving screening. From the administrative data we assembled, we could not determine whether this reduction in screening occurs because clinicians fail to recommend the test to this population, fail to follow-up on that recommendation, or due to other factors. Nevertheless, our data indicate that SUD per se appears to correlate with reduced utilization of screening.
Our study did not find that the prevalence of diagnosed osteoporosis was elevated in the psychosis group compared to controls (). Other studies in similar populations have found higher rates of osteoporosis. For example, a recent study which used broadband ultrasound attenuation found that bone mass in women with schizophrenia under age 50 was significantly lower than healthy controls; however, broadband attenuation values were similar in groups in those over 50 years (15
). A study by our group found that bone mineral density as measured by dual-energy x-ray absorptiometry (DXA) is also lower in middle-aged women with schizophrenia than in same-age healthy controls (14
). However, substance use was not examined in these reports. Though not observed as a significant finding in our full population age 50–64, our post-hoc analysis of women age 55–64 found that SUD might significantly impact osteoporosis prevalence. For those oldest subjects, there was more than a 6-times increase (OR=6.7) in the observed prevalence of osteoporosis for the group with the diagnosis of psychosis and SUD together, although the psychosis or substance use diagnoses alone demonstrated no such increased prevalence.
Alcohol and drugs of abuse have been associated with an increased risk of osteoporosis and fracture (29
), particularly in the older population (31
). In a Swedish study 20% of all patients with hip fracture during a two-year period were in people with alcohol and drug abuse (32
). Furthermore, early menopause is associated with a greater risk of osteoporosis, and drug use has been found to be associated with a 2.6 fold increased risk for early menopause (33
). Amenorrhea from prolactin elevating antipsychotics has also been suggested to increase osteoporosis risk in women with schizophrenia and long term cumulative exposure may explain the higher risk in the older ages. However, because we did not observe a significant risk of osteoporosis in the non-SUD psychotic disorders group, this may suggest that comorbid substance use plays a significant role and may partially explain the higher rates of bone loss seen in other studies where substance use was not reported (12
). Whatever the explanation, the convergence of both the diagnosis of schizophrenia and substance use in our subpopulation of women age 55–64 correlates with elevated risk of osteoporosis. Consistent with this apparent life-stage finding, we have recently completed another study using dual-energy x-ray absorptiometry (DXA) in older (> 50 years) patients and found that those who smoke or are alcohol dependent had a significantly greater bone mass loss (17
Other interesting findings of the current study include the following. First, women of Black race were significantly less likely to receive screening for osteoporosis, as has been reported previously (35
), yet were also less likely to be diagnosed with this disorder. There is evidence to suggest that Black women are at a decreased risk for osteoporosis and our findings parallel these reports (37
). It is not clear however if the decreased prevalence noted in our study is an artifact of decreased screening or truly represents a lower risk in this population. Regarding race, it is noteworthy that the apparent prevalence of major mood disorder in Black women was substantially lower than in White women (209/9690, 2.2% versus 456/7968, 5.7%; ). This project was not designed to evaluate diagnostic racial disparities, however this finding is interesting in view of previously observed disparities in treating and possibly diagnosing mood disorders in minority populations (39
). Lastly, although prevalence of screening was similar among patients with mood disorders and controls ( and ), risk of osteoporosis was significantly elevated in those with mood disorders (see ). People within this diagnostic category were 37% more likely to develop osteoporosis compared to the control group. This diagnostic group may be at increased risk of osteoporosis that may be related to other mechanisms than those associated with substance use or psychotic disorders (40
). Osteoporosis in women with mood disorders might be elevated due in part to hypercortisolemia and maintaining a hyperadrenergic state (41
), or increases in interleukin 6, one of the most potent known bone resorption factors. Additionally, recent evidence suggests that antidepressants also may contribute to risk of osteoporosis (43
). It should finally be noted here that reverse causality may be partially in play regarding this observed association, i.e., that osteoporosis may lead to depression because the disease is associated with deteriorating physical health.
A limitation of our study is that our estimate of prevalence rates for osteoporosis comes from administrative records of treatment, rather than direct screening of the entire sample, and thus could potentially miss large numbers of undiagnosed cases. Thus, we would interpret the apparently similar prevalence of osteoporosis () in women with SUD and controls, despite lower screening rates (), as a signal that osteoporosis is likely under-diagnosed in women with SUD. Prevalence of osteoporosis is higher in women with mood disorders compared with controls even while screening rates are comparable in both groups. This may reflect appropriate and targeted testing, or it might, again, suggest that the mood disorder group may have a true prevalence of osteoporosis that is even higher than reported, due to inadequate screening in this high risk group. Accordingly, Medicaid records are not as sensitive to prevalence as epidemiologic survey data that typically have higher potential to obtain untreated or otherwise undisclosed pathology. The apparent prevalence of substance use in this population of women age 50–64 was 7.2%, of whom 11% had co-morbid diagnoses of psychosis. While the overall population rate (7.2%) is on par with epidemiologic studies including younger adults, the rate of substance use as a co-morbidity to psychosis was only 11.4%- lower than the 50% lifetime prevalence anticipated (44
). In Medicaid reporting, the principal disease (psychosis) and its treatment may eclipse reporting of comorbid substance abuse because it is not relevant to reimbursement expectations. In addition, formally diagnosed SUD is known to be lower than the actual rates of such illness (45
). The Epidemiological Catchment Area (ECA) study reported a prevalence of 6.1% for drug/alcohol abuse and dependence in the general population (46
) and the most recent National Comorbidity Survey reported 3.8% for drug/alcohol abuse or dependence (47
) similar to what we have observed here. In evaluating our reported prevalence of the co-morbid substance abuse and psychosis, it is important to keep in mind that our derived rates are annual and not life-time prevalence figures. Our figures furthermore reflect late-life prevalence and therefore may seem lower than expected (42
). While lifetime alcohol use rates have been reported to be as high as 77% in schizophrenia, at any point in time, current prevalence of alcohol abuse or dependence is generally reported to be around 20% (48
). Occasional and lifetime use would not necessarily be included in administrative data as it, by design, emphasizes contemporary diagnostic and treatment events.
Another limitation to this study is the fact that the logistic regression model results predicted only 1 and 4 percent of the variance regarding screening or osteoporosis rates, respectively. Though significant, much remains unexplained regarding who received screening or who is at risk for disease. For example, we were unable to control for obesity, smoking status, diet, exercise and other unknown factors in this analysis, but this type of information is difficult to gather in even a prospective design. Medication use, particularly antipsychotic exposure and prescriptions for treatment (e.g., biphosphonates) were not analyzed. Future work would benefit from considering such ancillary and direct treatment variables. Lastly, although the majority of people with schizophrenia and psychotic disorders in the US are receiving Medicaid benefits (18
), generalizability of these findings across groups is questionable because the sample size of the control group was considerably larger than the diagnostic groups, and some of the diagnostic groupings were quite small. Finally, it remains unclear if SUD leads to lower rates for all preventive health screening or if this is specific to DXA and other bone density scanning. There is little published literature on this topic in an SUD population and more research is needed in this area.
In conclusion, screening rates for osteoporosis in people with schizophrenia are low but do not differ from the general population of those on Medicaid. However, this population may be at greater risk if they are substance users/abusers, thereby increasing the potential need for screening for such persons. Additionally, screening rates for those with substance abuse problems in isolation also appear to be below those for most other Medicaid enrollees. Accordingly, it appears that efforts should be made to increase osteoporosis prevention and treatment in those with substance abuse problems and especially in those who also have co-morbid psychosis (50
). The higher rates of diagnosed osteoporosis among older women with major mood disorders indicate that this group, also, may require more extensive screening.