Polypharmacy and Potentially Inappropriate Medication Use in Older Adults With Systemic Lupus Erythematosus.

OBJECTIVE: To assess the prevalence and potential risk factors for polypharmacy and prescribing of the potentially inappropriate medications, opioids and benzodiazepines/Z-drugs, in older adults with systemic lupus erythematosus (SLE). METHODS: The study population comprised adults age ≥50 years meeting American College of Rheumatology or Systemic Lupus International Collaborating Clinics classification criteria followed at a tertiary care rheumatology clinic. Information on prescriptions filled in the 4 months preceding chart review was obtained from the Manitoba Drug Program Information Network. Clinical data, including age, sex, Charlson Comorbidity Index (CCI) score, Systemic Lupus Erythematosus Disease Activity Index 2000 score, prednisone use, SLE duration, and rural residence were abstracted from electronic medical records. Logistic regression analyses were performed to assess any association between polypharmacy (using 2 definitions: ≥5 and ≥10 medications), potentially inappropriate medication use, and clinical features. RESULTS: A total of 206 patients (mean age 62 years, 91% female, 36% rural) were included: 148 (72%) filled ≥5 medications, 71 (35%) filled ≥10 medications, 63 (31%) used benzodiazepines/Z-drugs, and 50 (24%) used opioids. Among the 77 patients age ≥65 years, 57 (74%) filled ≥5 medications, and 26 (34%) filled ≥10 medications, compared to 30% and 4%, respectively, of Manitobans age ≥65 years (National Prescription Drug Utilization Information System, 2016). The odds of polypharmacy were greater with prednisone use (adjusted odds ratio [OR] 3.70 [95% confidence interval (95% CI) 1.40-9.79] for ≥5 medications), CCI score (adjusted OR 1.62 [95% CI 1.20-2.17]), and rural residence (adjusted OR 2.05 [95% CI 1.01-4.18]). Odds of benzodiazepine/Z-drug use were increased with polypharmacy (adjusted OR 4.35 [95% CI 1.69-11.22]), and odds of opioid use were increased with polypharmacy (adjusted OR 6.75 [95% CI 1.93-23.69]) and CCI score (adjusted OR 1.29 [95% CI 1.08-1.54]). CONCLUSION: The prevalence of polypharmacy in this SLE cohort was higher than in the general Manitoban population. Polypharmacy is a strong marker for use of prescription benzodiazepines/Z-drugs and opioids.

Cancer Risk in a Large Inception Systemic Lupus Erythematosus Cohort: Effects of Demographic Characteristics, Smoking, and Medications.

OBJECTIVE: To assess cancer risk factors in incident systemic lupus erythematosus (SLE). METHODS: Clinical variables and cancer outcomes were assessed annually among incident SLE patients. Multivariate hazard regression models (overall risk and most common cancers) included demographic characteristics and time-dependent medications (corticosteroids, antimalarial drugs, immunosuppressants), smoking, and the adjusted mean Systemic Lupus Erythematosus Disease Activity Index 2000 score. RESULTS: Among 1,668 patients (average 9 years follow-up), 65 cancers occurred: 15 breast, 10 nonmelanoma skin, 7 lung, 6 hematologic, 6 prostate, 5 melanoma, 3 cervical, 3 renal, 2 each gastric, head and neck, and thyroid, and 1 each rectal, sarcoma, thymoma, and uterine cancers. Half of the cancers (including all lung cancers) occurred in past/current smokers, versus one-third of patients without cancer. Multivariate analyses indicated that overall cancer risk was related primarily to male sex and older age at SLE diagnosis. In addition, smoking was associated with lung cancer. For breast cancer risk, age was positively associated and antimalarial drugs were negatively associated. Antimalarial drugs and higher disease activity were also negatively associated with nonmelanoma skin cancer risk, whereas age and cyclophosphamide were positively associated. Disease activity was associated positively with hematologic and negatively with nonmelanoma skin cancer risk. CONCLUSION: Smoking is a key modifiable risk factor, especially for lung cancer, in SLE. Immunosuppressive medications were not clearly associated with higher risk except for cyclophosphamide and nonmelanoma skin cancer. Antimalarials were negatively associated with breast cancer and nonmelanoma skin cancer risk. SLE activity was associated positively with hematologic cancer and negatively with nonmelanoma skin cancer. Since the absolute number of cancers was small, additional follow-up will help consolidate these findings.

Impact of Psychiatric Comorbidity on Health Care Use in Rheumatoid Arthritis: A Population-Based Study.

OBJECTIVE: Psychiatric comorbidity is frequent in rheumatoid arthritis (RA) and complicates treatment. The present study was undertaken to describe the impact of psychiatric comorbidity on health care use (utilization) in RA. METHODS: We accessed administrative health data (1984-2016) and identified a prevalent cohort with diagnosed RA. Cases of RA (n = 12,984) were matched for age, sex, and region of residence with 5 controls (CNT) per case (n = 64,510). Within each cohort, we identified psychiatric morbidities (depression, anxiety, bipolar disorder, and schizophrenia [PSYC]), with active PSYC defined as ≥2 visits per year. For the years 2006-2016, annual rates of ambulatory care visits (mean ± SD per person) categorized by provider (family physician [FP], rheumatologist, psychiatrist, other specialist), hospitalization (% of cohort), days of hospitalization (mean ± SD), and dispensed drug types (mean ± SD per person) were compared among 4 groups (CNT, CNT plus PSYC, RA, and RA plus PSYC) using generalized linear models adjusted for age, sex, rural versus urban residence, income quintile, and total comorbidities. Estimated rates are reported with 95% confidence intervals (95% CIs). We tested within-person and RA-PSYC interaction effects. RESULTS: Subjects with RA were mainly female (72%) and urban residents (59%), with a mean ± SD age of 54 ± 16 years. Compared to RA without PSYC, RA with PSYC had more than additive (synergistic) visits (standardized mean difference [SMD] 10.92 [95% CI 10.25, 11.58]), hospitalizations (SMD 13% [95% CI 0.11, 0.14]), and hospital days (SMD 3.63 [95% CI 3.06, 4.19]) and were dispensed 6.85 more medication types (95% CI 6.43, 7.27). Cases of RA plus PSYC had increased visits to FPs (an additional SMD 8.92 [95% CI 8.35, 9.46] visits). PSYC increased utilization in within-person models. CONCLUSION: Managing psychiatric comorbidity effectively may reduce utilization in RA.

Validity and Reliability of Screening Measures for Depression and Anxiety Disorders in Rheumatoid Arthritis.

OBJECTIVE: To test the validity and reliability of screening instruments for depression and anxiety in rheumatoid arthritis (RA). METHODS: Participants with RA completed the Patient Health Questionnaire (PHQ-2 or PHQ-9), the Patient Reported Outcomes Measurement Information System depression short form 8a and anxiety short form 8a, the Hospital Anxiety and Depression Scale anxiety score (HADS-A) and depression score (HADS-D), the Overall Anxiety Severity and Impairment Scale, the Generalized Anxiety Disorder 2- and 7-item scales, and the Kessler-6 scale. Clinical depression and anxiety disorders were confirmed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I Disorders (SCID-1) research version. We reported sensitivity, specificity, positive predictive value, and negative predictive value using SCID-1 diagnoses as the criterion standard. Test-retest reliability was assessed with the intraclass correlation coefficient. RESULTS: Of 150 participants, 11.3% had SCID-1-diagnosed depression, 7.3% had SCID-1-diagnosed generalized anxiety disorder, and 19.3% had any SCID-1-diagnosed anxiety disorder. For depression, sensitivity ranged from HADS-D (cut point 11; 35%) to PHQ-2 (88%) and PHQ-9 (87%). Specificity ranged from PHQ-9 (77%) and PHQ-2 (84%) to HADS-D (cut point 11; 94%). Positive predictive value ranged from 30% to 43%. Negative predictive value ranged from 92% to 98%. For generalized anxiety disorder, sensitivity ranged from HADS-A (cut point 11; 45%) to HADS-A (cut point 8; 91%). Specificity ranged from 81% to 89% for all measures except the HADS-A (cut point 8; 63%). Intraclass correlation coefficient estimates ranging from 0.69 to 0.88 confirmed good test-retest reliability. CONCLUSION: Depression screening instruments had good diagnostic performance; anxiety instruments were more variable. Identified depression and anxiety require clinical confirmation.

Economic Evaluation of Lupus Nephritis in the Systemic Lupus International Collaborating Clinics Inception Cohort Using a Multistate Model Approach.

OBJECTIVE: Little is known about the long-term costs of lupus nephritis (LN). The costs were compared between patients with and without LN using multistate modeling. METHODS: Patients from 32 centers in 11 countries were enrolled in the Systemic Lupus International Collaborating Clinics inception cohort within 15 months of diagnosis and provided annual data on renal function, hospitalizations, medications, dialysis, and selected procedures. LN was diagnosed by renal biopsy or the American College of Rheumatology classification criteria. Renal function was assessed annually using the estimated glomerular filtration rate (GFR) or estimated proteinuria. A multistate model was used to predict 10-year cumulative costs by multiplying annual costs associated with each renal state by the expected state duration. RESULTS: A total of 1,545 patients participated; 89.3% were women, the mean ± age at diagnosis was 35.2 ± 13.4 years, 49% were white, and the mean followup duration was 6.3 ± 3.3 years. LN developed in 39.4% of these patients by the end of followup. Ten-year cumulative costs were greater in those with LN and an estimated glomerular filtration rate (GFR) <30 ml/minute ($310,579 2015 Canadian dollars versus $19,987 if no LN and estimated GFR >60 ml/minute) or with LN and estimated proteinuria >3 gm/day ($84,040 versus $20,499 if no LN and estimated proteinuria <0.25 gm/day). CONCLUSION: Patients with estimated GFR <30 ml/minute incurred 10-year costs 15-fold higher than those with normal estimated GFR. By estimating the expected duration in each renal state and incorporating associated annual costs, disease severity at presentation can be used to anticipate future health care costs. This is critical knowledge for cost-effectiveness evaluations of novel therapies.

Increased Incidence of Critical Illness in Psoriasis.

BACKGROUND: Psoriasis is associated with an increased risk of comorbid disease. Despite the recognition of increased morbidity in psoriasis, the effects on health care utilisation remain incompletely understood. Little is known about the risk of intensive care unit (ICU) admission in persons with psoriasis. OBJECTIVE: To compare the incidence of ICU admission and post-ICU mortality rates in a psoriasis population compared with a matched population without psoriasis. METHODS: Using population-based administrative data from Manitoba, Canada, we identified 40 930 prevalent cases of psoriasis and an age-, sex-, and geographically matched cohort from the general population (n = 150 210). We compared the incidence of ICU admission between populations using incidence rates and Cox regression models adjusted for age, sex, socioeconomic status, and comorbidity and compared mortality after ICU admission. RESULTS: Among incident psoriasis cases (n = 30 150), the cumulative 10-year incidence of ICU admission was 5.6% (95% confidence interval [CI], 5.3%-5.8%), 21% higher than in the matched cohort (incidence rate ratio, 1.21; 95% CI, 1.15-1.27). In the prevalent psoriasis cohort, crude mortality in the ICU was 11.5% (95% CI, 9.9%-13.0%), 32% higher than observed in the matched population admitted to the ICU (8.7%; 95% CI, 8.3%-9.1%). Mortality rates after ICU admission remained elevated at all time points in the psoriasis cohort compared with the matched cohort. CONCLUSION: Psoriasis is associated with an increased risk for ICU admission and with an increased risk of mortality post-ICU admission.

Development of the Lupus Interactive Navigator as an Empowering Web-Based eHealth Tool to Facilitate Lupus Management: Users Perspectives on Usability and Acceptability.

BACKGROUND: Systemic Lupus Erythematosus (SLE) is a serious, complex, and chronic illness. Similar to most other chronic illness states, there is great interest in helping persons with SLE engage in their disease management. OBJECTIVE: The objectives of this study were to (1) develop the Lupus Interactive Navigator (LIN), a web-based self-management program for persons with SLE, and (2) test the LIN for usability and acceptability. METHODS: The LIN development platform was based on the results of preliminary comprehensive needs assessments and adapted from the Oncology Interactive Navigator, a web-based tool developed for persons with cancer. Medical researchers, writers, designers, and programmers worked with clinical experts and persons with SLE to develop content for the LIN. Usability and acceptability of the LIN was tested on individuals with SLE meeting American College of Rheumatology criteria, who were recruited from five Canadian SLE clinics. Participants were provided with access to the LIN and were asked to use it over a two-week period. Following the testing period, participants were contacted for a 30-minute telephone interview to assess usability and acceptability. RESULTS: The content for the LIN was subdivided into six primary information topics with interview videos featuring rheumatologists, allied health professionals, and persons with SLE. Usability and acceptability of the LIN was tested on 43 females with SLE. Of these, 37 (86%) completed telephone interviews. The average age was 43.6 (SD 15.9) years and disease duration averaged 14.1 (SD 10.8) years. Median time spent on LIN was 16.3 (interquartile range [IQR]:13.7, 53.5) minutes and median number of sessions was 2 (IQR: 1, 3). Overall, Likert ratings (0=strongly disagree; 7=strongly agree) of website usability and content were very high, with 75% scoring >6 out of 7 on all items. All participants agreed that LIN was easy to use, would recommend it to others with SLE, and would refer to it for future questions about SLE. Very high ratings were also given to relevancy, credibility, and usefulness of the information provided. Overall, 73% of the participants rated all topics helpful to very helpful. Participants who reported more prior knowledge about SLE rated items regarding improvement in knowledge and helpfulness relatively lower than persons with less prior knowledge. Most participants commented that the LIN would be very useful to those newly diagnosed with SLE. Minor revisions were recommended. CONCLUSIONS: This study furthers the understanding of the needs in the SLE community and delivers a unique eHealth tool to promote self-management in persons with SLE. The LIN was found to be highly acceptable in content and usability. The information provided on LIN may be most helpful for individuals with less experience with the disease, such as those newly diagnosed, indicating the need to tailor the content for persons with more SLE experience.

A Longitudinal Analysis of Outcomes of Lupus Nephritis in an International Inception Cohort Using a Multistate Model Approach.

OBJECTIVE: To study bidirectional change and predictors of change in estimated glomerular filtration rate (GFR) and proteinuria in lupus nephritis (LN) using a multistate modeling approach. METHODS: Patients in the Systemic Lupus International Collaborating Clinics inception cohort were classified annually into estimated GFR state 1 (>60 ml/minute), state 2 (30-60 ml/minute), or state 3 (<30 ml/minute) and estimated proteinuria state 1 (<0.25 gm/day), state 2 (0.25-3.0 gm/day), or state 3 (>3.0 gm/day), or end-stage renal disease (ESRD) or death. Using multistate modeling, relative transition rates between states indicated improvement and deterioration. RESULTS: Of 1,826 lupus patients, 700 (38.3%) developed LN. During a mean ± SD follow-up of 5.2 ± 3.5 years, the likelihood of improvement in estimated GFR and estimated proteinuria was greater than the likelihood of deterioration. After 5 years, 62% of patients initially in estimated GFR state 3 and 11% of patients initially in estimated proteinuria state 3 transitioned to ESRD. The probability of remaining in the initial states 1, 2, and 3 was 85%, 11%, and 3%, respectively, for estimated GFR and 62%, 29%, and 4%, respectively, for estimated proteinuria. Male sex predicted improvement in estimated GFR states; older age, race/ethnicity, higher estimated proteinuria state, and higher renal biopsy chronicity scores predicted deterioration. For estimated proteinuria, race/ethnicity, earlier calendar years, damage scores without renal variables, and higher renal biopsy chronicity scores predicted deterioration; male sex, presence of lupus anticoagulant, class V nephritis, and mycophenolic acid use predicted less improvement. CONCLUSION: In LN, the expected improvement or deterioration in renal outcomes can be estimated by multistate modeling and is preceded by identifiable risk factors. New therapeutic interventions for LN should meet or exceed these expectations.

Predictors of ICU Admission and Outcomes 1 Year Post-Admission in Persons with IBD: A Population-based Study.

BACKGROUND: To determine predictors of intensive care unit (ICU) admission and to assess health care utilization (HCU) post-ICU admission among persons with inflammatory bowel disease (IBD). METHODS: We matched a population-based database of Manitobans with IBD to a general population cohort on age, sex, and region of residence and linked these cohorts to a population-based ICU database. We compared the incidence rates of ICU admission among prevalent IBD cases according to HCU in the year before admission using generalized linear models adjusting for age, sex, socioeconomic status, region, and comorbidity. Among incident cases of IBD who survived their first ICU admission, we compared HCU with matched controls who survived ICU admission. RESULTS: Risk factors for ICU admission from the year before admission included cumulative corticosteroid use (incidence rate ratio, 1.006 per 100 mg of prednisone; 95% confidence interval, 1.004-1.008) and IBD-related surgery (incidence rate ratio, 2.79; 95% confidence interval, 1.99-3.92). Use of immunomodulatory therapies within 1 year, or surgery for IBD beyond 1 year prior, were not associated with ICU admission. In those who used corticosteroids and immunomodulatory medications in the year before ICU admission, the use of immunomodulatory medications conferred a 30% risk reduction in ICU admission (incidence rate ratio, 0.70; 95% confidence interval, 0.50-0.97). Persons with IBD who survived ICU admission had higher HCU in the year following ICU discharge than controls. CONCLUSIONS: Corticosteroid use and surgery within the year are associated with ICU admission in IBD while immunomodulatory therapy is not. Surviving ICU admission is associated with high HCU in the year post-ICU discharge.

Lymphoma risk in systemic lupus: effects of disease activity versus treatment.

OBJECTIVE: To examine disease activity versus treatment as lymphoma risk factors in systemic lupus erythematosus (SLE). METHODS: We performed case-cohort analyses within a multisite SLE cohort. Cancers were ascertained by regional registry linkages. Adjusted HRs for lymphoma were generated in regression models, for time-dependent exposures to immunomodulators (cyclophosphamide, azathioprine, methotrexate, mycophenolate, antimalarial drugs, glucocorticoids) demographics, calendar year, Sjogren's syndrome, SLE duration and disease activity. We used adjusted mean SLE Disease Activity Index scores (SLEDAI-2K) over time, and drugs were treated both categorically (ever/never) and as estimated cumulative doses. RESULTS: We studied 75 patients with lymphoma (72 non-Hodgkin, three Hodgkin) and 4961 cancer-free controls. Most lymphomas were of B-cell origin. As is seen in the general population, lymphoma risk in SLE was higher in male than female patients and increased with age. Lymphomas occurred a mean of 12.4 years (median 10.9) after SLE diagnosis. Unadjusted and adjusted analyses failed to show a clear association of disease activity with lymphoma risk. There was a suggestion of greater exposure to cyclophosphamide and to higher cumulative steroids in lymphoma cases than the cancer-free controls. CONCLUSIONS: In this large SLE sample, there was a suggestion of higher lymphoma risk with exposure to cyclophosphamide and high cumulative steroids. Disease activity itself was not clearly associated with lymphoma risk. Further work will focus on genetic profiles that might interact with medication exposure to influence lymphoma risk in SLE.

Non-lymphoma hematological malignancies in systemic lupus erythematosus.

OBJECTIVE: To describe non-lymphoma hematological malignancies in systemic lupus erythematosus (SLE). METHODS: A large SLE cohort was linked to cancer registries. We examined the types of non-lymphoma hematological cancers. RESULTS: In 16,409 patients, 115 hematological cancers [including myelodysplastic syndrome (MDS)] occurred. Among these, 33 were non-lymphoma. Of the 33 non-lymphoma cases, 13 were of lymphoid lineage: multiple myeloma (n = 5), plasmacytoma (n = 3), B cell chronic lymphocytic leukemia (B-CLL; n = 3), precursor cell lymphoblastic leukemia (n = 1) and unspecified lymphoid leukemia (n = 1). The remaining 20 cases were of myeloid lineage: MDS (n = 7), acute myeloid leukemia (AML; n = 7), chronic myeloid leukemia (CML; n = 2) and 4 unspecified leukemias. Most of these malignancies occurred in female Caucasians, except for plasma cell neoplasms (4/5 multiple myeloma and 1/3 plasmacytoma cases occurred in blacks). CONCLUSIONS: In this large SLE cohort, the most common non-lymphoma hematological malignancies were myeloid types (MDS and AML). This is in contrast to the general population, where lymphoid types are 1.7 times more common than myeloid non-lymphoma hematological malignancies. Most (80%) multiple myeloma cases occurred in blacks; this requires further investigation.

Association of smoking with cutaneous manifestations in systemic lupus erythematosus.

OBJECTIVE: To examine the association between smoking and cutaneous involvement in systemic lupus erythematosus (SLE). METHODS: We analyzed data from a multicenter Canadian SLE cohort. Mucocutaneous involvement was recorded at the most recent visit using the Systemic Lupus Erythematosus Disease Activity Index 2000 Update (rash, alopecia, and oral ulcers), Systemic Lupus International Collaborating Clinics/American College of Rheumatology (ACR) Damage Index (alopecia, extensive scarring, and skin ulceration), and the ACR revised criteria for SLE (malar rash, discoid rash, photosensitivity, and mucosal involvement). Multivariate logistic regression models were used to estimate the independent association between mucocutaneous involvement and cigarette smoking, age, sex, ethnicity, lupus duration, medications, and laboratory data. RESULTS: In our cohort of 1,346 patients (91.0% women), the mean ± SD age was 47.1 ± 14.3 years and the mean ± SD disease duration was 13.2 ± 10.0 years. In total, 41.2% of patients were ever smokers, 14.0% current smokers, and 27.1% past smokers. Active mucocutaneous manifestations occurred in 28.4% of patients; cutaneous damage occurred in 15.4%. Regarding the ACR criteria, malar rash was noted in 59.5%, discoid rash in 16.9%, and photosensitivity in 55.7% of patients. In the multivariate analysis, current smoking was associated with active SLE rash (odds ratio [OR] 1.63 [95% confidence interval (95% CI) 1.07, 2.48]). Having ever smoked was associated with ACR discoid rash (OR 2.36 [95% CI 1.69, 3.29]) and photosensitivity (OR 1.47 [95% CI 1.11, 1.95]), and with the ACR total cutaneous score (OR 1.50 [95% CI 1.22, 1.85]). We did not detect any associations between previous smoking and active cutaneous manifestations. No association was found between smoking and cutaneous damage or mucosal ulcers. No interaction was seen between smoking and antimalarials. CONCLUSION: Current smoking is associated with active SLE rash, and ever smoking with the ACR total cutaneous score. This provides additional motivation for smoking cessation in SLE.

Cancer risk in systemic lupus: an updated international multi-centre cohort study.

OBJECTIVE: To update estimates of cancer risk in SLE relative to the general population. METHODS: A multisite international SLE cohort was linked with regional tumor registries. Standardized incidence ratios (SIRs) were calculated as the ratio of observed to expected cancers. RESULTS: Across 30 centres, 16,409 patients were observed for 121,283 (average 7.4) person-years. In total, 644 cancers occurred. Some cancers, notably hematologic malignancies, were substantially increased (SIR 3.02, 95% confidence interval, CI, 2.48, 3.63), particularly non-Hodgkin's lymphoma, NHL (SIR 4.39, 95% CI 3.46, 5.49) and leukemia. In addition, increased risks of cancer of the vulva (SIR 3.78, 95% CI 1.52, 7.78), lung (SIR 1.30, 95% CI 1.04, 1.60), thyroid (SIR 1.76, 95% CI 1.13, 2.61) and possibly liver (SIR 1.87, 95% CI 0.97, 3.27) were suggested. However, a decreased risk was estimated for breast (SIR 0.73, 95% CI 0.61-0.88), endometrial (SIR 0.44, 95% CI 0.23-0.77), and possibly ovarian cancers (0.64, 95% CI 0.34-1.10). The variability of comparative rates across different cancers meant that only a small increased risk was estimated across all cancers (SIR 1.14, 95% CI 1.05, 1.23). CONCLUSION: These data estimate only a small increased risk in SLE (versus the general population) for cancer over-all. However, there is clearly an increased risk of NHL, and cancers of the vulva, lung, thyroid, and possibly liver. It remains unclear to what extent the association with NHL is mediated by innate versus exogenous factors. Similarly, the etiology of the decreased breast, endometrial, and possibly ovarian cancer risk is uncertain, though investigations are ongoing.

Pregnancy and the risk of rheumatoid arthritis in a highly predisposed North American Native population.

OBJECTIVE: To examine reproductive history and rheumatoid arthritis (RA) risk in a highly predisposed population of North American Natives (NAN) with unique fertility characteristics. METHODS: The effect of pregnancy on the risk of RA was examined by comparing women enrolled in 2 studies: a study of RA in NAN patients and their unaffected relatives; and NAN patients with RA and unrelated healthy NAN controls enrolled in a study of autoimmunity. All participants completed questionnaires detailing their reproductive history. RESULTS: Patients with RA (n = 168) and controls (n = 400) were similar overall in age, education, shared epitope frequency, number of pregnancies, age at first pregnancy, smoking, and breastfeeding history. In multivariate analysis, for women who had ≥ 6 births the OR for developing RA was 0.43 (95% CI 0.21-0.87) compared with women who had 1-2 births (p = 0.046); for women who gave birth for the first time after age 20 the OR for developing RA was 0.33 (95% CI 0.16-0.66) compared with women whose first birth occurred at age ≤ 17 (p = 0.001). The highest risk of developing RA was in the first postpartum year (OR 3.8; 95% CI 1.45-9.93) compared with subsequent years (p = 0.004). CONCLUSION: In this unique population, greater parity significantly reduced the odds of RA; an early age at first birth increased the odds, and the postpartum period was confirmed as high risk for RA onset. The protective effect of repeated exposure to the ameliorating hormonal and immunological changes of pregnancy may counterbalance the effect of early exposure to the postpartum reversal of these changes.