Impact of Lifestyle and Socioeconomic Position on the Association Between Non-steroidal Anti-inflammatory Drug Use and Major Adverse Cardiovascular Events: A Case-Crossover Study

INTRODUCTION

It is unknown whether the cardiovascular risks associated with non-steroidal anti-inflammatory drug (NSAID) use differ according to lifestyle and socioeconomic position.

OBJECTIVE

We examined the association between NSAID use and major adverse cardiovascular events (MACE) within subgroups defined by lifestyle and socioeconomic position.

METHODS

We conducted a case-crossover study of all adult first-time respondents to the Danish National Health Surveys of 2010, 2013, or 2017, without previous cardiovascular disease, who experienced a MACE from survey completion through 2020. We used a Mantel-Haenszel method to obtain odds ratios (ORs) of the association between NSAID use (ibuprofen, naproxen, or diclofenac) and MACE (myocardial infarction, ischemic stroke, heart failure, or all-cause death). We identified NSAID use and MACE via nationwide Danish health registries. We stratified the analyses by body mass index, smoking status, alcohol consumption, physical activity level, marital status, education, income, and employment.

RESULTS

Compared with non-use, the OR of MACE was 1.34 (95% confidence interval: 1.23-1.46) for ibuprofen, 1.48 (1.04-2.43) for naproxen, and 2.18 (1.72-2.78) for diclofenac. When comparing NSAID use with non-use or the individual NSAIDs with each other, we observed no notable heterogeneity in the ORs within subgroups of lifestyle and socioeconomic position for any NSAID. Compared with ibuprofen, diclofenac was associated with increased risk of MACE in several subgroups with high cardiovascular risk, e.g., individuals with overweight (OR 1.52, 1.01-2.39) and smokers (OR 1.54, 0.96-2.46).

CONCLUSIONS

The relative increase in cardiovascular risk associated with NSAID use was not modified by lifestyle or socioeconomic position.

Long-Term Risk of Hospitalization for Somatic Diseases Among Survivors of Childhood Acute Lymphoblastic Leukemia

Background

Survivors of childhood acute lymphoblastic leukemia (ALL) may be at increased long-term risk of hospitalization for somatic diseases. However, large population-based cohort studies with risk estimates for survivors successfully cured without experiencing a relapse or requiring hematopoietic stem cell transplantation (HSCT) are lacking.

Methods

Danish and Swedish patients diagnosed with ALL before age 20 years in 1982-2008 were identified in the national cancer registries. Five-year survivors and matched population comparisons without childhood cancer were followed for hospitalization for 120 somatic disease categories in the national hospital registries from 5 years postdiagnosis until 2017, and disease-specific hospitalization rate ratios (RR) were calculated. The mean cumulative count method was used to estimate the mean number of multiple and recurrent disease-specific hospitalizations per individual.

Results

A total of 2024 5-year survivors and 9797 population comparisons were included. The overall hospitalization rate was more than twice as high compared with comparisons (RR = 2.30, 95% confidence interval [CI] = 2.09 to 2.52). At 30 years postdiagnosis, the mean cumulative hospitalization count was 1.69 (95% CI = 1.47 to 1.90) per survivor and 0.80 (95% CI = 0.73 to 0.86) per comparison. In the subcohort without relapse or HSCT (n = 1709), the RR was 1.41 (95% CI = 1.27 to 1.58).

Conclusions

Survivors of childhood ALL were at increased long-term risk for disease-specific hospitalizations; however, in survivors without relapse or HSCT, the rate was only modestly higher than in population comparisons without a childhood cancer. The absolute mean numbers of multiple and recurrent hospitalizations were generally low.

The Incidence of Breast Cancer Recurrence 10-32 Years after Primary Diagnosis

Background

Extended, more effective breast cancer treatments have increased the prevalence of long-term survivors. We investigated the risk of late breast cancer recurrence (BCR), 10 years or more after primary diagnosis, and associations between patient and tumor characteristics at primary diagnosis and late BCR up to 32 years after primary breast cancer diagnosis.

Methods

Using the Danish Breast Cancer Group clinical database, we identified all women with an incident early breast cancer diagnosed during 1987-2004. We restricted to women who survived 10 years without a recurrence or second cancer (10-year disease-free survivors) and followed them from 10 years after breast cancer diagnosis date until late recurrence, death, emigration, second cancer, or December 31, 2018. We calculated incidence rates per 1000 person-years and cumulative incidences for late BCR, stratifying by patient and tumor characteristics. Using Cox regression, we calculated adjusted hazard ratios for late BCR accounting for competing risks.

Results

Among 36 924 women with breast cancer, 20 315 became 10-year disease-free survivors. Of these, 2595 developed late BCR (incidence rate = 15.53 per 1000 person-years, 95% confidence interval = 14.94 to 16.14; cumulative incidence = 16.6%, 95% confidence interval = 15.8% to 17.5%) from year 10 to 32 after primary diagnosis. Tumor size larger than 20 mm, lymph node–positive disease, and estrogen receptor–positive tumors were associated with increased cumulative incidences and hazards for late BCR.

Conclusions

Recurrences continued to occur up to 32 years after primary diagnosis. Women with high lymph node burden, large tumor size, and estrogen receptor–positive tumors had increased risk of late recurrence. Such patients may warrant extended surveillance, more aggressive treatment, or new therapy approaches.

Post-traumatic stress disorder and incident fractures in the Danish population

Psychological stress may be associated with increased risk of fractures. It is unknown whether post-traumatic stress disorder (PTSD), a marker of chronic severe psychological stress occurring in response to a traumatic event, influences fracture risk. In this nationwide cohort study, persons with PTSD had an increased risk of fractures compared to the general population.

INTRODUCTION

We conducted a population-based national cohort study in Denmark to examine the association between PTSD and incident fractures.

METHODS

We examined the incidence rate of overall and specific fractures among patients with clinician-diagnosed PTSD (n = 4114), compared with the incidence rate in the general population from 1995 to 2013, using Danish medical registry data. We further examined differences in associations by gender, age, psychiatric and somatic comorbidity, and follow-up time. We calculated absolute risks, standardized incidence ratios (SIRs), and 95% confidence intervals (95% CIs).

RESULTS

Risk of any fracture among persons with PTSD was 24% (95% CI 20%, 28%) over the study period. The SIR for any fracture was 1.7 (95% CI 1.6, 1.9). We found little evidence of effect measure modification of the association between PTSD and fractures in our stratified analyses.

CONCLUSIONS

Our findings suggest that PTSD is associated with increased fracture risk.

Abstract P6-08-14: Breast cancer risk in chronic users of phthalate-containing medications: A Danish nationwide cohort study

Background. Phthalates are ubiquitous in consumer goods (e.g., food containers, cosmetics, and pharmaceuticals), from which they readily leach into the environment. Phthalates interfere with hormonal signaling and may affect reproductive, developmental, and cancer endpoints. Preclinical evidence implicates some phthalates in breast cancer progression—particularly dibutyl phthalate (DBP), which potentiates the estrogen receptor (ER). Associations between phthalates and breast cancer incidence have not been thoroughly investigated. Users of phthalate-containing medications have up to 70-fold higher urinary phthalate levels than other individuals, and represent a highly exposed population for efficient study of phthalate health effects.

Methods. We used the Danish Drug Information Database to identify all phthalate-containing oral medications marketed during the study period. We recorded the product code and the type and mass of phthalate per pill. We identified a nationwide cohort of women at risk for a first cancer between 2005—2015, and who had no previous exposure to a phthalate-containing drug. Using the National Prescription Registry we characterized time-varying, medication-borne phthalate exposure. Incident cancers were ascertained by linking to the Danish Cancer Registry. We fit Cox regression models to estimate associations between cumulative phthalate exposures and breast cancer incidence. Exposures were updated annually and lagged by 1 year. We adjusted for established risk factors, comorbidity, co-medications (e.g., HRT), and drug substances exposed to.

Results. We identified 481 products from 24 drug classes containing either DBP, diethyl phthalate (DEP), cellulose acetate phthalate (CAP), hypromellose phthalate (HPMCP), or polyvinyl acetate phthalate (PVAP). Drugs with phthalate-containing products also included phthalate-free products. Phthalate masses ranged from 3 µg to 1.3 g per pill. We followed 1.12 million women over 9.99 million person-years, during which 27,111 women were diagnosed with invasive breast cancer. Fourteen percent of the cohort (n=161,751) was prescribed a phthalate-containing drug. We observed no breast cancer associations with exposure to CAP, DEP, HPMCP, and PVAP. However, the highest level of cumulative DBP exposure (>10,000 mg; range: 10,024 to 71,340 mg; median=15,390 mg) was associated with an 80% increase in breast cancer risk compared with no exposure (HRadj=1.8; 95% CI: 1.0, 3.1). The association was strongest for ER+ disease (HRadj=1.9; 95% CI: 1.1, 3.5) and among premenopausal women (HRadj=2.2; 95% CI: 0.91, 5.3). There was no evidence of a linear trend in the log-hazard across categories of cumulative DBP exposure. No published evidence links exposure to the drug substances represented by the DBP-containing products (bisacodyl, budesonide, mesalazine, multienzymes, diclofenac, and lithium) with breast cancer risk.

Conclusions. High DBP exposure was associated with increased breast cancer incidence, particularly ER+ disease and among premenopausal women. This association merits further investigation. In the meantime, it may be prudent for women taking DBP-containing medications to substitute a phthalate-free version of the same drug, other considerations being equal.

Citation Format: Ahern TP, Cronin-Fenton DP, Broe A, Pilgaard Ulrichsen S, Cole BF, Lash TL, Toft Sørensen H, Tamimi RM, Damkier P. Breast cancer risk in chronic users of phthalate-containing medications: A Danish nationwide cohort study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-08-14.

Abstract P3-12-05: Serum levels of the active tamoxifen metabolite Z-4OHtam is predictive of long-term survival in luminal B subtype of breast cancer patients

Background

Tamoxifen (tam) is the main adjuvant endocrine treatment option in premenopausal breast cancer (BC) patients comprising luminal-like tumors. However, a significant proportion of tam-users will experience a relapse within 15 years of primary surgery. We postulate that some patients do not achieve the full clinical benefit of tam due to inter-individual differences in the metabolism of the drug and that the clinical relevance of this may be different between molecular subtypes of BC. Here, we have compared the prognostic value of threshold levels of active tam metabolites in PAM50 luminal (lum) A and B molecular subtypes.

Material and Methods

A number of 64 lum-like BC patients who were relapse-free 3 years after surgery, were retrospectively analyzed in the observational Oslo1 study. All patients received 20 mg tamoxifen daily for 5 years. Serum was obtained at the time of the 3 years follow-up. A sensitive and accurate LC-MS/MS method was developed and validated for the detection and quantification of tam and 9 metabolites in human serum. The median follow-up time from serum sampling to BC death or last follow-up was 13.9 years (0.6-16.5). Recurrence score and molecular subtype of the patients were determined on FFPE-tumor samples using the PAM50 classification algorithm.

Results

A linear trend was identified for the correlation between active metabolite Z-4OHtam and BCSS (p=0.021, HR=0.64, CI95=0.43–0.93). There was no linear association between the remaining metabolites and BC outcome. We further explored the possible association between survival and concentration thresholds for the active metabolites Z-4OHtam and Z-endoxifen and identified supervised cut off values representing low concentrations for Z-4OHtam (≤3.26 nM) and Z-endoxifen (≤9.00 nM). BC patients with low Z-4OHtam had a BCSS of 33.3% compared to 82.8% in patients with Z-4OHtam >3.26 nM (p<0.001, logrank; HR=6.83, CI 95=2.09-22.36). Lum status (A vs B; HR=5.50, CI95= 1.66-18.25) and Z-4OHtam concentration status (high vs low; HR=6.05, CI95=1.74-21.06) were the only factors left in the final multivariable model. A log-linear relationship between the ROR score and BCSS (p=0.002, HR=1.09, CI95=1.03–1.15) was identified after adjustment of clinically relevant variables and lum status was highly prognostic, (Lum A vs B; p=0.001, HR=5.2, CI=1.72-15.46). Therefore, we wanted to compare the prognostic value of the Z-4OHtam threshold in patients subgroups stratified by lum status. Low concentrations of Z-4OHtam were associated with poorer survival for patients in the lum B group only (HR=4.94, CI 95=1.16-21-02). For the lum A patients no significant association was found.

Discussion

Low levels (≤ 3.26 nM) of the active tam metabolite Z-4OHtam was associated with a poorer long-term outcome in tam-treated BC patients. However, when grouping patients according to the PAM50-based molecular subtype, this was only significant in patients belonging to the lum B subtype. Our results suggest that higher levels of active tam metabolites and thus better ER blockage are more important in the more aggressive lum B subtype.

Citation Format: Helland T, Søiland H, Hustad S, Lash TL, Kvaløy JT, Renolen A, Borgen E, Bifulco E, Henne N, Lien EA, Mellgren G, Naume B, Janssen EA. Serum levels of the active tamoxifen metabolite Z-4OHtam is predictive of long-term survival in luminal B subtype of breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-12-05.

Abstract P3-07-23: CYP2D6 genotype and breast cancer recurrence in tamoxifen treated patients: An evaluation of the importance of loss-of-heterozygosity

Background: Tamoxifen therapy for estrogen receptor positive (ER+) breast cancer reduces recurrence risk by about half. Steady-state concentrations of endoxifen, a potent anti-estrogenic tamoxifen metabolite, are reduced in women whose CYP2D6 genotypes confer poor enzyme function. Many studies have measured associations between genetically impaired CYP2D6 function and tamoxifen resistance. It has been suggested that the subset of studies using DNA extracted from tumor-infiltrated tissue may have been susceptible to genotyping error induced by loss of heterozygosity (LOH); the putative non-differential genotype misclassification may have biased these studies' estimates toward the null. We reviewed the clinical epidemiology studies conducted to date to assess the importance of loss-of-heterozygosity (LOH) at the CYP2D6 locus and its implications for assessing tamoxifen effectiveness.

Methods: We searched for the terms "tamoxifen" and "CYP2D6" in PubMed, including all papers and abstracts through 31 May 2015 on the association of CYP2D6 gene variants and the risk of breast cancer recurrence or mortality. We used a quantitative bias analysis (QBA) to evaluate the importance of genotype misclassification in studies that extracted DNA from tumor-infiltrated tissue. We conducted a random effects meta-analysis to evaluate all studies simultaneously, and within groups according to whether DNA was derived from tumor-infiltrated tissue or non-neoplastic tissue.

Results: Thirty-one studies investigated CYP2D6 genotype and breast cancer recurrence, yielding relative effect estimates ranging from 0.08 to 14. DNA was extracted from blood or non-neoplastic tissue in 21 of these 31 studies (68%), and from tumor-infiltrated tissue in the remaining 10 (32%). Our analysis of the association between variant/variant genotype compared with wildtype/wildtype genotype included 21 of the 31 studies. Sixteen (76%) of these 21 studies extracted DNA from blood or non-neoplastic tissue and five (24%) extracted DNA from tumor-infiltrated tissue. Genotype misclassification parameters for the QBA were estimated from six concordance studies. There was little difference between the effect estimates (EE) and 95% confidence/simulation intervals (95% CI/SI) before and after QBA (EE=1.71, 95%CI=1.24, 2.36, and 1.80 95%SI=1.28, 2.54, respectively). Studies using non-neoplastic DNA had higher variance than those based on tumor-infiltrated tissue DNA, half reported implausibly high EE, and many were susceptible to design and analysis errors that would bias estimates of association away from the null.

Conclusions: We found little relative bias in the summary estimates of association, either overall or when limited to the tumor-infiltrated tissue DNA studies. Three guideline panels, based on robust evidence, recommend against CYP2D6 genotype-guided tamoxifen therapy. Alternatives for optimizing the effectiveness of tamoxifen therapy, such as assuring adherence and persistence, are more likely to achieve clinically important benefits.

Citation Format: Ahern TP, Hertz DL, Damkier P, Ejlertsen B, Hamilton-Dutoit SJ, Rae JM, Regan MM, Thompson AM, Lash TL, Cronin-Fenton DP. CYP2D6 genotype and breast cancer recurrence in tamoxifen treated patients: An evaluation of the importance of loss-of-heterozygosity. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-23.

Glucocorticoid prescriptions and breast cancer recurrence: a Danish nationwide prospective cohort study

BACKGROUND

Treatment with synthetic glucocorticoids (GCs) depresses the immune response and may therefore modify cancer outcomes. We investigated the association between GC use and breast cancer recurrence.

MATERIALS AND METHODS

We conducted a population-based cohort study to examine the risk of breast cancer recurrence associated with GC use among incident stage I-III female breast cancer patients aged >18 years diagnosed 1996-2003 in Denmark. Data on patients, clinical and treatment factors, recurrence, and comorbidities as well as data on GC prescriptions and potential confounders were obtained from Danish population-based medical registries. GCs were categorized according to administrative route: systemic, inhaled, or intestinal. Women were followed for up to 10 years or until 31 December 2008. We used Cox proportional hazards regression models to compute hazard ratios (HRs) and associated 95% confidence intervals (95% CIs) to evaluate the association between GC use and recurrence. Time-varying drug exposures were lagged by 1 year.

RESULTS

We included 18 251 breast cancer patients. Median recurrence follow-up was 6.9 years; 3408 women developed recurrence during follow-up. Four thousand six hundred two women filled at least one GC prescription after diagnosis. In unadjusted models, no association was observed among users of systemic, inhaled, and intestinal GCs (HRsystemic = 1.1, 95% CI 0.9-1.3; HRinhaled = 0.9, 95% CI 0.7-1.0; and HRintestinal = 1.0, 95% CI 0.9-1.2) versus nonusers. In adjusted models, the results were also near null (HRsystemic = 1.1, 95% CI 0.9-1.2; HRinhaled = 0.8, 95% CI 0.7-1.0; and HRintestinal = 1.0, 95% CI 0.8-1.2).

CONCLUSION

We found no evidence of an effect of GC use on breast cancer recurrence.

Rosiglitazone use and post-discontinuation glycaemic control in two European countries, 2000-2010

OBJECTIVES

To evaluate the impact of risk minimisation policies on the use of rosiglitazone-containing products and on glycaemic control among patients in Denmark and the UK.

DESIGN, SETTING AND PARTICIPANTS

We used population-based data from the Aarhus University Prescription Database (AUPD) in northern Denmark and from the General Practice Research Database (GPRD) in the UK.

MAIN OUTCOME MEASURES

We examined the use of rosiglitazone during its entire period of availability on the European market (2000-2010) and evaluated changes in the glycated haemoglobin (HbA1c) and fasting plasma glucose (FPG) levels among patients discontinuing this drug.

RESULTS

During 2000-2010, 2321 patients with records in AUPD used rosiglitazone in northern Denmark and 25 428 patients with records in GPRD used it in the UK. The proportion of rosiglitazone users among all users of oral hypoglycaemic agents peaked at 4% in AUPD and at 15% in GPRD in May 2007, the month of publication of a meta-analysis showing increased cardiovascular morbidity associated with rosiglitazone use. 12 months after discontinuation of rosiglitazone-containing products, the mean change in HbA1c was -0.16% (95% CI -3.4% to 3.1%) in northern Denmark and -0.17% (95% CI -0.21% to 0.13%) in the UK. The corresponding mean changes in FPG were 0.01 mmol/L (95% CI -7.3 to 7.3 mmol/L) and 0.03 mmol/L (95% CI -0.22 to 0.28 mmol/L).

CONCLUSIONS

Publication of evidence concerning the potential cardiovascular risks of rosiglitazone was associated with an irreversible decline in the use of rosiglitazone-containing products in Denmark and the UK. The mean changes in HbA1c and FPG after drug discontinuation were slight.

Does comorbidity interact with colorectal cancer to increase mortality? A nationwide population-based cohort study

BACKGROUND

It is unknown whether comorbidity interacts with colorectal cancer (CRC) to increase the rate of mortality beyond that explained by the independent effects of CRC and comorbid conditions.

METHODS

We conducted a cohort study (1995-2010) of all Danish CRC patients (n=56963), and five times as many persons from the general population (n=271670) matched by age, gender, and specific comorbidities. To analyse comorbidity, we used the Charlson Comorbidity Index (CCI) scores. We estimated standardised mortality rates per 1000 person-years, and calculated interaction contrasts as a measure of the excess mortality rate not explained by the independent effects of CRC or comorbidities.

RESULTS

Among CRC patients with a CCI score=1, the 0-1 year mortality rate was 415 out of 1000 person-years (95% confidence interval (CI): 401, 430) and the interaction accounted for 9.3% of this rate (interaction contrast=39 out of 1000 person-years, 95% CI: 22, 55). For patients with a CCI score of 4 or more, the interaction accounted for 34% of the mortality (interaction contrast=262 out of 1000 person-years, 95% CI: 215, 310). The interaction between CRC and comorbidities had limited influence on mortality beyond 1 year after diagnosis.

CONCLUSION

Successful treatment of the comorbidity is pivotal and may reduce the mortality attributable to comorbidity itself, and also the mortality attributable to the interaction.

Mortality and incidence of new primary cancers in men with prostate cancer: a Danish population-based cohort study

BACKGROUND

Prostate cancer (PC) survivors may have an increased risk of new primary cancers (NPCs) due to shared risk factors or PC-directed treatments.

METHODS

Using Danish registries, we conducted a cohort study of men with (n=30,220) and without PC (n=151,100) (comparators), matched 1:5 on age and PC diagnosis/index date. We computed incidence rates of NPCs per 10,000 person years (PY) and associated 95% confidence intervals (CI), and used Cox proportional hazards regression to compute hazard ratios (HRs) and 95%CI, adjusting for comorbidities. In order to obviate any impact of shorter survival among prostate cancer patients, we censored comparator patients when the matched prostate cancer patient died or was censored.

RESULTS

Follow-up spanned 113,487PY and 462,982PY in the PC and comparison cohorts, respectively. 65% of the cohorts were aged >70 years at diagnosis. Among PC patients, 51% had distant/unspecified stage, and 63% had surgery as primary treatment. The PC cohort had lower incidence of NPCs than their comparators. The adjusted HR of NPC among men with PC versus the comparators was 0.84 (95%CI=0.80, 0.88). Lowest HRs were among older men, those with distant stage, and were particularly evident for cancers of the brain, liver, pancreas, respiratory, upper gastrointestinal, and urinary systems.

CONCLUSIONS

We find no evidence of an increased risk of NPCs among men with PC. The deficit of NPCs among men with PC may be a true effect but is more likely due to lower levels of risk factors (e.g., smoking) in PC patients versus comparators, clinical consideration of cancers at new organs as metastases rather than new primaries, or under-recording/under-reporting of NPCs among PC patients.

Antidepressant use and colorectal cancer risk: a Danish population-based case-control study

Background:

Earlier research suggests that use of selective serotonin reuptake inhibitors (SSRIs), but not tricyclic antidepressants (TCAs), reduces the risk of colorectal cancer (CRC).

Methods:

We conducted a population-based case–control study to investigate the association between antidepressant use and CRC risk. Cases were diagnosed with a first primary CRC from 1991 through 2008. We selected 10 population controls matched to cases on sex, birth year, and residence from the Danish Civil Registration System using risk-set sampling. We estimated the odds ratios (ORs) and 95% confidence intervals (CIs) associating antidepressant use with colorectal cancer occurrence, controlling for potential confounders.

Results:

The study included 9979 cases and 99 790 controls. We found no notable reduction in CRC risk in ever users (⩾2 prescriptions) of TCAs (OR=0.94; 95% CI: 0.84, 1.05), SSRIs (OR=0.97; 95% CI: 0.90, 1.05), or other antidepressants (OR=0.95; 95% CI: 0.83, 1.07). Associations for recent and former use of antidepressants were also near null. Intensity of antidepressant use (number of pills divided by total duration of use), regardless of duration, was not associated with CRC risk.

Conclusions:

We found no evidence that antidepressant use substantially reduces the risk of colorectal cancer.

Antiplatelet drugs and risk of subarachnoid hemorrhage: a population-based case-control study

SUMMARY BACKGROUND

Antiplatelet drug use increases bleeding risk, but its role in precipitating subarachnoid hemorrhage remains unclear.

OBJECTIVES

We examined whether the use of low-dose acetylsalicylic acid (LDA), clopidogrel or dipyridamole increased the risk of subarachnoid hemorrhage.

PATIENTS/METHODS

This population-based case-control study was conducted in northern Denmark. We used the Danish National Patient Registry to identify all persons admitted to neurosurgery or neurology departments with a first diagnosis of subarachnoid hemorrhage between 1997 and 2008 (n = 1186). Using risk-set sampling, we selected 10 population controls (n = 11 840) for each case, matched by age and sex. We obtained data on prescriptions for antiplatelet drugs, use of other medications and comorbidity from medical databases. We used conditional logistic regression to compute odds ratios with 95% confidence intervals (CIs), controlling for confounding factors.

RESULTS

One hundred and nine cases (9.2%) and 910 controls (7.7%) used antiplatelet drugs. Among cases, 104 (8.8%) used LDA and 11 (0.9%) used dipyridamole. Among controls, 891 (7.5%) used LDA and 48 (0.4%) used dipyridamole. As compared with not using any antiplatelet drugs during the study period, the adjusted odds ratios were 1.03 (95% CI 0.81-1.32) for long-term LDA use, 2.52 (95% CI 1.37-4.62) for new LDA use, and 2.09 (95% CI 1.04-4.23) for long-term dipyridamole use. Owing to the low number of users, data were inconclusive for clopidogrel.

CONCLUSIONS

Long-term dipyridamole use and new LDA use were associated with an increased risk of subarachnoid hemorrhage. Because of the limited precision of these risk estimates, however, caution is advised in their interpretation. Long-term LDA use was not associated with subarachnoid hemorrhage.

Statins and amyotrophic lateral sclerosis--the level of evidence for an association

Myopathy is a known side effect of statins, but neurotoxicity is not. Two studies reported that statins and amyotrophic lateral sclerosis (ALS) appear together more than expected amongst adverse events in overlapping surveillance databases. A pooled analysis of clinical trials, many with short follow-up, showed no higher rate of ALS in the statins arms. In older age groups, statin use increased from approximately 5% in 1991 to approximately 40% in 1998 and then remained constant. There was no similar increase in ALS incidence. The initial signals of a strong association from drug surveillance systems should now be discounted, but not disregarded.

Comorbidity and survival of Danish breast cancer patients from 1995 to 2005

Comorbid diseases can affect breast cancer prognosis. We conducted a population-based study of Danish women diagnosed with a first primary breast cancer from 1995 to 2005 (n=9300), using hospital discharge registry data to quantify comorbidities by Charlson score. We examined the influence of comorbidities on survival, and quantified their impact on relative mortality rates. The prevalence of patients with a Charlson score='0' fell from 86 to 81%, with an increase in those with Charlson score='1-2' from 13 to 16%, and score='3+' from 1 to 2%. One- and five-year survival for patients with Charlson score='0' and '1-2' was better for those diagnosed in 1998-2000 than in 1995-1997. Overall, patients diagnosed in 2001-2004 (mortality ratio (MR)=0.80, 95% CI=0.68-0.95) and 1998-2000 (MR=0.92, 95% CI=0.78-1.09) had lower 1-year age-adjusted mortality compared to those diagnosed in 1995-1997 (reference period). Patients with Charlson scores '1-2' and '3+' had higher age-adjusted 1-year mortality than those with a Charlson score='0' in each time period (2001-2004: MR('1-2')=1.76, 95% CI=1.35-2.30, and MR('3+')=3.78, 95% CI=2.51-5.68; and 1998-2000: MR('1-2')=1.60, 95% CI=1.36-1.88 and MR('3+')=2.34, 95% CI=1.65-3.33). Similar findings were observed for 5-year age-adjusted mortality. Additional analyses, adjusted for stage, indicated that confounding by stage could not explain these findings. Despite continued improvements in breast cancer survival, we found a trend of poorer survival among breast cancer patients with severe comorbidities even after adjusting for age and stage. Such poorer survival is an important public health concern and can be expected to worsen as the population ages.

Birth outcome in women with breast cancer

We investigated whether maternal breast cancer affects birth outcome in a nationwide cohort study of 695 births from 1973 to 2002 of women with breast cancer with respect to preterm birth, low birth weight at term, stillbirth and congenital abnormalities as well as mean birth weight, compared with the outcomes of 33 443 births from unaffected mothers. There was no excess risk of adverse birth outcome for the 216 newborns of women with breast cancer before pregnancy. Stratification by mother's treatment did not change the results. For 37 newborns of women diagnosed during pregnancy, the prevalence ratio (PR) of preterm birth was 8.1 (95% confidence interval (CI): 3.8–17). However, 10 of the 12 preterm deliveries among these women were elective early deliveries. Among 442 births of women diagnosed in the 2 years from time of delivery, the PR of preterm birth was 1.4 (95% CI: 1.0–2.0), and the PR of low birth weight at term for boys was 2.9 (95% CI: 1.3–6.3). Overall, our results are reassuring regarding the risks of adverse birth outcome for breast cancer patients.

Accuracy of ovarian cancer ICD-10 diagnosis in a Danish population-based hospital discharge registry

OBJECTIVE

We estimated the accuracy of ICD-10 diagnosis of ovarian cancer in a Danish discharge registry (HDR) by comparing it with Cancer Registry data (DCR).

STUDY DESIGN AND SETTING

Patients (N=489) living in North Jutland County, Denmark with ovarian cancer or borderline tumour registered in the HDR or the DCR. We estimated the completeness and positive predictive value (PPV) of ovarian cancer discharge diagnosis. Mortality rates were constructed for both registries.

RESULTS

The completeness in the HDR for ovarian cancer was 96% (95% confidence interval [CI]: 94%-98%) and PPV was 87% (95% CI: 85%-90%). 87 (18%) of the patients coded with ovarian cancer in the HDR had borderline tumours. When borderline tumours were excluded from the DCR, the PPV declined to 69% and the completeness did not change. The mortality rate ratio for ovarian cancer registered in the HDR compared to the DCR was 1.08 (95% CI: 0.90-1.29).

CONCLUSION

The discharge data (ICD-10) had some misclassification, but can be a valuable tool in assessment of the prognosis of ovarian cancer.

Medical surveillance after breast cancer diagnosis

OBJECTIVES

To characterize the tests ordered for surveillance of breast cancer recurrence in the 4 years after breast cancer diagnosis by surgeons, medical oncologists, and radiation oncologists.

RESEARCH DESIGN

303 stage I or II breast cancer patients age 55-years or older and diagnosed at 1 of 5 Boston hospitals. Patient interviews and medical record abstracts provided the data to characterize patient demographics, the breast cancer stage and its primary therapy, and the surveillance procedures ordered.

RESULTS

279 of the 303 women had some surveillance testing. Among those who received some surveillance, a mean of 22.0 tests were ordered, most by their medical oncologists (mean = 14.4), followed by their surgeons (mean = 9.7) and their radiation oncologists (mean = 5.7). The most common test was a mammogram (mean = 3.9). Women ages 75 to 90 years old were at higher risk for failure to complete four consecutive years of surveillance and for receipt of less than guideline surveillance. Younger women, women treated at a breast cancer center with a unified patient chart, and women who worked full or part time were at lower risk for failure to complete 4 years of surveillance.

CONCLUSION

Most women in this cohort received some surveillance after completing primary therapy for breast cancer. Although no woman's surveillance corresponded exactly to existing guidelines, the oldest women were least likely to receive guideline surveillance. Surveillance after breast cancer therefore joins the list of aspects of breast cancer care-breast cancer screening, diagnosis, prognostic evaluation, and primary therapy-for which older women receive less than definitive care.

A comparison of the National Death Index and Social Security Administration databases to ascertain vital status

We compared vital status follow-up by the National Death Index and the Social Security Administration for a cohort of breast cancer patients. Only the National Death Index allowed follow-up for subjects with an unknown Social Security number. All of the deaths identified by the Social Security Administration were reported by the National Death Index. No subject reported to be alive by the Social Security Administration matched a National Death Index record. Subjects with inaccurate identifying information were more effectively followed up by the National Death Index. The National Death Index more accurately reported dates of death.

Adjuvant tamoxifen: predictors of use, side effects, and discontinuation in older women

PURPOSE

To identify predictors of adjuvant tamoxifen use, side effects, and discontinuation in older women.

PATIENTS AND METHODS

We followed a cohort of 303 women > or = 55 years of age diagnosed with stage I or stage II breast cancer for nearly 3 years. Data were collected from women's surgical records and from computer-assisted telephone interviews at 5, 21, and 33 months after primary tumor therapy.

RESULTS

Two hundred ninety-two (96%) of 303 patients in the study provided information about tamoxifen use. Tamoxifen use was reported by 189 patients (65%); 26 (15%) discontinued use during the follow-up period. Patients who were 65 to 74 years of age (relative to those 55 to 64 years of age), had stage II disease, were estrogen receptor-positive, saw a greater number of breast cancer physicians, and had better perceptions of their abilities to discuss treatment options with physicians had greater odds of tamoxifen use. Those who had better physical function, had received standard primary tumor therapy, and had obtained helpful breast cancer information from books or magazines had lesser odds of tamoxifen use. Patients > or = 75 years of age (relative to those 55 to 64 years of age) and patients with better emotional health had significantly lesser odds of reporting side effects. Patients who were estrogen receptor-positive were less likely to stop taking tamoxifen; patients who experienced side effects were more likely to stop taking tamoxifen.

CONCLUSION

Deviations from a prescribed course of adjuvant tamoxifen occur relatively frequently. The clinical consequences of this deviation need to be identified.

The effect of less than definitive care on breast carcinoma recurrence and mortality

BACKGROUND

Risk factors for breast carcinoma offer few opportunities for prevention; thus, the reduction of morbidity and mortality among breast carcinoma patients must remain a priority. The objective of this study was to measure the effects of less than definitive care for patients with breast carcinoma on disease recurrence and mortality.

METHODS

The prognostic evaluation and treatment received by an inception cohort of 494 women was characterized. Three hundred ninety women ages 45-90 years with local or regional breast carcinoma who were diagnosed between 1984 and 1986 and were treated at one of eight Rhode Island hospitals comprised the final cohort. Disease recurrence and mortality were ascertained through December 31, 1996. Candidate determinants of outcomes were a less than definitive prognostic evaluation and less than definitive primary therapy-adjusted for confounding by patient age, extent of disease, and comorbid diseases.

RESULTS

During the first 5 years of follow-up, patients who received a less than definitive prognostic evaluation had an adjusted relative hazard of recurrence of 1.7 (95% confidence interval, 1.0-2.7) and an adjusted relative hazard for breast carcinoma mortality of 2.2 (95% confidence interval, 1.2-3.9). Patients who received less than definitive therapy had an adjusted relative hazard of recurrence of 1.6 (95% confidence interval, 1.0-2.5), and an adjusted relative hazard of breast carcinoma mortality of 1.7 (95% confidence interval, 1.0-2.8).

CONCLUSIONS

Breast carcinoma patients who receive less than definitive care are at excess risk for disease recurrence and mortality. Women with early stage breast carcinoma should be treated in accordance with existing guidelines.

A sensitivity analysis to separate bias due to confounding from bias due to predicting misclassification by a variable that does both

Variables that predict misclassification of exposure, outcome, or a confounder cannot be controlled by techniques that adjust for predictors of risk. They must be controlled by external adjustments. We confronted an analysis in which a variable predicted misclassification of the exposure and of a confounder. The same variable confounded the exposure-outcome relation. The analysis focused on the relation between less-than-definitive therapy and breast cancer mortality in the 5 years after diagnosis. Receipt of less-than-definitive prognostic evaluation predicted misclassification of definitive therapy (the exposure) and stage (a confounder). Prognostic evaluation also confounded the therapy-breast cancer mortality relation. We used a sensitivity analysis to separate the misclassification biases from the confounding bias. The relative hazard associated with less-than-definitive therapy in the original multivariable model equaled 1.75 (95% confidence interval = 1.02-3.00). The median estimate in 2,500 repetitions of the sensitivity analysis was a relative hazard of 1.64, and 90% of the estimates fell between 1.47 and 1.83. The sensitivity analysis suggests that less-than-definitive therapy confers an excess relative hazard of breast cancer mortality in the 5 years after diagnosis. The original analysis, which adjusted for confounding by prognostic evaluation but not its misclassification biases, overestimated the relative hazard.

Patient characteristics and treatments associated with a decline in upper-body function following breast cancer therapy

Breast cancer therapy is often followed by a decline in upper-body function. Women (303) diagnosed with stage I or II breast cancer were interviewed 5 and 21 months after surgery and their medical records were reviewed. Women with cardiopulmonary comorbidity had an odds ratio for decline at the 5-month interview of 2.8 (95% CI 1.3-5. 7), relative to women without. Women who received mastectomy (OR = 2. 5; 95% CI 0.9-6.7) or breast-conserving surgery with radiation therapy (OR = 2.9; 95% CI 1.0-8.9) were at higher risk for decline at the 5-month interview than women who received only breast-conserving surgery. Women who had axillary dissection were more likely to report numbness or pain in the axilla (OR = 6.4; 95% CI 1.2-33) at the 21-month interview than women who did not. Clinicians should consider the functional consequences of treatment when discussing treatment options and postoperative care with women who have early stage breast cancer.

Lifestyle determinants of cancer among Danish mastic asphalt workers

Three reports suggest that asphalt workers, especially young mastic asphalt workers, in Denmark experience an increase in incidence and mortality from cancer and in mortality from other conditions. The methodology described in these reports raises questions about their validity and the data presented are limited and difficult to interpret. The cancers and the causes of death that are increased are highly correlated with those seen among men in the general population who use alcohol in excess, who smoke, and who engage in other risk-taking behaviors. The effects of these lifestyle causes of disease were largely not controlled in the reported studies. These behaviors, which cluster in young men, rather than exposure to asphalt fumes, probably caused the disease patterns that were reported. Policy makers who use epidemiologic results for risk assessment and regulation should do so with care. Working men and women sometimes die at high rates and their occupational exposures may or may not be responsible. The distinction is crucial if occupational health is to be improved. If asphalt workers die young from excessive drinking and smoking, we are not protecting their health by controlling asphalt fume exposures.

Comparison of interview-based and medical-record based indices of comorbidity among breast cancer patients

OBJECTIVES

To compare patient interview-based and medical-record based measures of comorbidity and their relation to primary tumor therapy, all cause mortality, self-reported upper body function, and overall physical function.

METHODS

Three-hundred and three breast cancer patients (> or = 55 years) who were diagnosed in 1 of 5 Boston hospitals were enrolled. Patient interviews and medical record abstracts provided the information necessary to construct the Charlson index, Satariano index, and a new interview-based index of cardiopulmonary comorbidity. Those indices were used alone and in combination to predict the patient outcomes.

RESULTS

The indices of comorbidity corresponded well with one another. No index of comorbidity predicted mortality or receipt of definitive primary therapy. The new interview-based index of cardiopulmonary comorbidity was a better predictor of upper body function and overall physical function than was the interview-based or medical record-based Charlson or Satariano indices of comorbidity.

CONCLUSION

Older breast cancer patients are able to provide information about their diseases and related symptoms that correlates well with medical record-based measures of comorbidity and displays similar patterns of predictive power. A new self-reported measure of cardiopulmonary comorbidity performs better than the medical record-based measures for predicting patient related functional outcomes.

Active and passive cigarette smoking and the occurrence of breast cancer

Using a case-control design, the authors studied female residents of five Massachusetts towns between 1983 and 1986. The objective was to measure the associations between breast cancer occurrence and exposure to active and passive cigarette smoke. Until recently, exposure to tobacco smoke has not been thought to cause breast cancer. Novel perspectives on measuring the association of tobacco smoke with the occurrence of breast cancer and studies of genetically susceptible populations argue for further investigation. In this study, the authors found that ever-active smokers had an odds ratio of 2.0 (95 percent confidence interval (CI) 1.1-3.6) when compared with never-active, never-passive smokers. Women who smoked only before their first pregnancy (odds ratio = 5.6, 95 percent CI 1.5-21) and women who quit smoking 5-15 years before their index year (odds ratio = 3.9, 95 percent CI 1.4-10) were at the highest risk. Passive-only smokers had an odds ratio of 2.0 (95 percent CI 1.1-3.7) when compared with never-active, never-passive smokers. Among those women who were exposed to passive smoke before age 12 years, the odds ratios were 4.5 (95 percent CI 1.2-16) for passive-only smokers and 7.5 (95 percent CI 1.6-36) for ever-active smokers. Women who were first exposed to passive smoke after age 12 years had lower, although still elevated, odds ratios. The pattern of associations between exposure to cigarette smoke and the occurrence of breast cancer comports with a model of breast carcinogenesis.

A meta-analysis of the relation between cumulative exposure to asbestos and relative risk of lung cancer

OBJECTIVES

To obtain summary measures of the relation between cumulative exposure to asbestos and relative risk of lung cancer from published studies of exposed cohorts, and to explore the sources of heterogeneity in the dose-response coefficient with data available in these publications.

METHODS

15 cohorts in which the dose-response relation between cumulative exposure to asbestos and relative risk of lung cancer has been reported were identified. Linear dose-response models were applied, with intercepts either specific to the cohort or constrained by a random effects model; and with slopes specific to the cohort, constrained to be identical between cohorts (fixed effect), or constrained by a random effects model. Maximum likelihood techniques were used for the fitting procedures and to investigate sources of heterogeneity in the cohort specific dose-response relations.

RESULTS

Estimates of the study specific dose-response coefficient (kappa 1.i) ranged from zero to 42 x 10(-3) ml/fibre-year (ml/f-y). Under the fixed effect model, a maximum likelihood estimate of the summary measure of the coefficient (k1) equal to 0.42 x 10(-3) (95% confidence interval (95% CI) 0.22 to 0.69 x 10(-3)) ml/f-y was obtained. Under the random effects model, implemented because there was substantial heterogeneity in the estimates of kappa 1.i and the zero dose intercepts (Ai), a maximum likelihood estimate of k1 equal to 2.6 x 10(-3) (95% CI 0.65 to 7.4 x 10(-3)) ml/f-y, and a maximum likelihood estimate of A equal to 1.36 (95% CI 1.05 to 1.76) were found. Industry category, dose measurements, tobacco habits, and standardisation procedures were identified as sources of heterogeneity.

CONCLUSIONS

The appropriate summary measure of the relation between cumulative exposure to asbestos and relative risk of lung cancer depends on the context in which the measure will be applied and the prior beliefs of those applying the measure. In most situations, the summary measure of effect obtained under the random effects model is recommended. Under this model, potency, k1, is fourfold lower than that calculated by the United States Occupational Safety and Health Administration.