Does levonorgestrel-releasing intrauterine system increase breast cancer risk in peri-menopausal women? An HMO perspective.

PURPOSE: To evaluate the association between levonorgestrel-releasing intrauterine system (LNG-IUS) use and breast cancer (BC) risk. METHODS: A cohort of all Maccabi Healthcare Services (MHS) female members aged 40-50 years between 1/2003 and 12/2013 was used to identify LNG-IUS users as "cases," and 2 age-matched non-users as "controls." Exclusion criteria included: prior BC diagnosis, prior (5 years pre-study) and subsequent treatment with other female hormones or prophylactic tamoxifen. Invasive tumors were characterized by treatments received (chemotherapy, hormonal therapy, trastuzumab, or combination thereof). RESULTS: The analysis included 13,354 LNG-IUS users and 27,324 controls (mean age: 44.1 ± 2.6 vs. 44.9 ± 2.8 years; p < 0.0001). No significant differences in 5-year Kaplan-Meier (KM) estimates for overall BC risk or ductal carcinoma in situ occurrence were observed between groups. There was a trend towards higher risk for invasive BC in LNG-IUS users (5-year KM-estimate: 1.06% vs. 0.93%; p = 0.051). This difference stemmed primarily from the younger women (40-45 years; 0.88% vs. 0.69%, p = 0.014), whereas in older women (46-50 years), it was non-significant (1.44% vs. 1.21%; p = 0.26). Characterization of invasive BC by treatment demonstrated that LNG-IUS users had similar proportions of tumors treated with hormonal therapy, less tumors treated with trastuzumab, (7.5% vs. 14.5%) and more tumors treated with chemotherapy alone (25.8% vs. 14.9%; p = 0.041). CONCLUSIONS: In peri-menopausal women, LNG-IUS was not associated with an increased total risk of BC, although in the subgroup of women in their early 40's, it was associated with a slightly increased risk for invasive tumors.

Database evaluation of the association between serum magnesium levels and the risk of atrial fibrillation in the community.

BACKGROUND: In population studies, mild hypomagnesemia, determined by a single measurement, was associated with incident atrial fibrillation, over ~20 years of follow-up. We sought to determine whether mild (≤ 1.7 mg/dL) and moderate (≤ 1.5mg/dL) hypomagnesemia are temporally associated with increased incidence of atrial fibrillation (AF) in the community. METHODS: Health Maintenance Organization (HMO) database cohort study including beneficiaries with ≥ 1 serum magnesium measurement between 2004 and 2013. The follow-up period was defined from the first magnesium measurement to first listing in an AF registry (for cases) and December 2013 or date of death or loss to follow-up (for controls). We analyzed the association between serum magnesium quintiles, as well as the above clinically relevant hypomagnesemia thresholds, and incident AF using Cox proportional hazard regression analysis, adjusting for confounders. The association between serum magnesium and AF occurring within 3 months was also examined. RESULTS: Among 162,162 subjects, 2228 (1.4%) developed AF over a median follow-up of 25.3 months. Compared to the middle quintile the lowest magnesium quintile (≤ 1.9 mg/dL) had a significantly higher risk of AF (HR, 1.21; 95% CI: 1.07-1.37). Increased AF risk was also associated with mild (HR, 1.44; 95% CI: 1.20-1.73) and moderate hypomagnesemia (HR, 1.57; 95% CI: 1.14-2.15). No association was found when limiting the follow-up period to 3 months. CONCLUSIONS: In our study, hypomagnesemia was associated with incident AF over prolonged but not short-term follow-up periods, suggesting that this association may not be causal.

The association of proton pump inhibitors and hypomagnesemia in the community setting.

Evidence for the association between hypomagnesemia and proton pump inhibitors (PPIs), highlighted by the 2011 FDA Drug Safety Communication, rests mainly on studies in hospitalized patients. Our objectives were to determine the prevalence of hypomagnesemia and its association with PPIs in the community setting. We performed a retrospective cross-sectional analysis of a large health maintenance organization administrative database, including ambulatory patients with ≥1 serum magnesium concentrations between 2008 and 2011, the lowest referred to as "index magnesium." In cases with any (index magnesium ≤0.7 mmol/L) or severe (≤0.55 mmol/L) hypomagnesemia, we analyzed (vs. controls, >0.7 mmol/L) the association with PPI or H2 -blocker use during the 4-12 months preceding the index magnesium by logistic regression analysis, adjusting for confounders. Among 95,205 subjects, 5,696 (6.0%) had any hypomagnesemia, which was severe in 454 (0.5%), with twofold higher prevalences in those with established risk factors. PPI use during the 4 months preceding the index magnesium was more common in cases of any hypomagnesemia (adjusted OR = 1.66; 95% CI, 1.55-1.78) and severe hypomagnesemia (adjusted OR = 3.79; 2.99-4.82) than in controls without acid suppression. Hypomagnesemia remained significantly associated with PPI use when using H2 -blocker-users as reference (adjusted OR = 1.25 [P = 0.003] and 2.65 [P < 0.001] for any and severe hypomagnesemia, respectively). We conclude that hypomagnesemia is associated with PPI use in ambulatory patients.

Hyperkalemia and renal function during monotherapy and dual renin-angiotensin blockade in the community setting.

BACKGROUND: In controlled trials, dual therapy with angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARBs) is associated with hyperkalemia and decreased renal function, but there is no information about these adverse effects in clinical practice. OBJECTIVE: The aim of this study was to assess the incidence of hyperkalemia and decreased renal function during dual therapy (ACE-I plus ARB) in a community-based setting. METHODS: In a retrospective cohort database study, we identified patients who received ARBs added to ongoing ACE-I therapy and who had at least 1 measurement of serum creatinine and potassium during each treatment period. We compared rates of hyperkalemia (>5.5 mmol/L) during equal periods of monotherapy and dual therapy and the rate of a significant rise in serum creatinine (≥0.5 mg/dL) between study periods. We assessed the impact of potential confounders on outcomes by logistic regression analysis. RESULTS: Among 425 patients (median follow-up 19 months for each treatment period), hyperkalemia was 2-fold more common during dual therapy than monotherapy (11.1% and 5.6% of patients, respectively) (relative risk = 1.96; 95% CI, 1.22-3.14; P < 0.001). In 77 patients with reduced renal function on monotherapy (serum creatinine ≥1.5 mg/dL), the rate of hyperkalemia was 20.8/100 patient-years, resulting in a number needed to harm of 10.1 patients, compared with 52.6 patients among those with preserved renal function. Mean serum creatinine between treatment periods increased >0.5 mg/dL in 7.5% of patients, more commonly in patients with decreased (18.2%) than with preserved (5.2%) baseline renal function (P < 0.001). CONCLUSION: In the community setting, dual therapy was associated with hyperkalemia and a decrease in renal function. The absolute risks were especially high among patients with reduced baseline renal function.

Potent CYP2D6 Inhibiting drugs do not increase relapse rate in early breast cancer patients treated with adjuvant tamoxifen.

Endoxifen, the most active metabolite of the prodrug tamoxifen, is produced by cytochrome P450 CYP2D6. Breast cancer patients treated with tamoxifen who have reduced CYP2D6 activity, related to either genetic variation or drug inhibition, may have inferior outcomes. To assess the effect of concomitant CYP2D6 inhibiting drug use on clinical outcomes of breast cancer patients treated with adjuvant tamoxifen. We conducted a retrospective database analysis. Women with non-metastatic estrogen receptor positive tumors who had completed adjuvant tamoxifen therapy for 2 years, without treatment with adjuvant aromatase inhibitors or early relapse, were included. Patients were classified as users of CYP2D6 inhibitors if they purchased strong CYP2D6 inhibiting drugs for ≥ 4 consecutive months during tamoxifen treatment. Tumors were classified as "high risk" if adjuvant chemotherapy was prescribed. Primary endpoint was disease free (DFS) and secondary endpoint was overall survival (OS). 902 patients treated with tamoxifen (median duration, 4.9 years) were followed for a median period of 5.9 years. Fifty-nine (6.5%) patients were users of CYP2D6 inhibitors (median duration, 23 months). DFS at 3 years (corresponding to 5 years after tamoxifen initiation) did not differ between users and non-users of CYP2D6 inhibiting drugs (92.7 vs. 93.0%, respectively; adjusted P = 0.44). OS at 3 years was lower in the patients using CYP2D6 inhibiting drugs: 89.4 vs. 93.8%, but after adjustment for age and comorbidities this difference was not significant (P = 0.20). Overall recurrence rates did not differ between users and non-users of CYP2D6 inhibiting drugs (11.8 vs. 19.0% respectively, P = 0.23). Concomitant prolonged therapy with strong CYP2D6 inhibiting drugs does not affect adversely DFS and recurrence rates in tamoxifen-treated early breast cancer patients.

In a population-based cohort of diabetes patients, men and women had similar risks for all-cause mortality.

OBJECTIVES: To compare death rates of diabetic men and women relative to the general population and to identify sex-specific risk factors for all-cause mortality. STUDY DESIGN AND SETTINGS: In the current historical prospective cohort study, standardized mortality ratios (SMRs) were calculated for 19,657 men and women with diabetes in a large Israeli health care organization compared to the mortality in the general population from 1999 to 2003. In addition, sex-specific survival analyses were performed for men and women separately using baseline data obtained between 1995 and 1999. RESULTS: During the study follow-up (90,899 person-years), 2,924 deaths were identified. The SMR for diabetic women (1.40; 95% confidence interval [CI]: 1.33, 1.47) was significantly (P<0.01) higher than for diabetic men (1.20; 95% CI: 1.14, 1.26). Age, glycated hemoglobin, serum creatinine, low-density lipoprotein, high-density lipoprotein, dialysis, use of angiotensin-converting enzyme inhibitors, and insulin were similarly associated with mortality in both sexes. Residing in the south of Israel was related with higher risk among men but with decreased risk among women. CONCLUSIONS: The study indicates that diabetes seems to eliminate the relative protection against death usually seen in women. It also suggests that most risk factors are comparable between the sexes, underlining the importance of similarly intensive disease management in diabetic women and in diabetic men.