Causal analyses with target trial emulation for real-world evidence removed large self-inflicted biases: systematic bias assessment of ovarian cancer treatment effectiveness.

BACKGROUND AND OBJECTIVES: Drawing causal conclusions from real-world data (RWD) poses methodological challenges and risk of bias. We aimed to systematically assess the type and impact of potential biases that may occur when analyzing RWD using the case of progressive ovarian cancer. METHODS: We retrospectively compared overall survival with and without second-line chemotherapy (LOT2) using electronic medical records. Potential biases were determined using directed acyclic graphs. We followed a stepwise analytic approach ranging from crude analysis and multivariable-adjusted Cox model up to a full causal analysis using a marginal structural Cox model with replicates emulating a reference randomized controlled trial (RCT). To assess biases, we compared effect estimates (hazard ratios [HRs]) of each approach to the HR of the reference trial. RESULTS: The reference trial showed an HR for second line vs. delayed therapy of 1.01 (95% confidence interval [95% CI]: 0.82-1.25). The corresponding HRs from the RWD analysis ranged from 0.51 for simple baseline adjustments to 1.41 (95% CI: 1.22-1.64) accounting for immortal time bias with time-varying covariates. Causal trial emulation yielded an HR of 1.12 (95% CI: 0.96-1.28). CONCLUSION: Our study, using ovarian cancer as an example, shows the importance of a thorough causal design and analysis if one is expecting RWD to emulate clinical trial results.

Predicting optimal treatment regimens for patients with HR+/HER2- breast cancer using machine learning based on electronic health records.

Aim: To predict optimal treatments maximizing overall survival (OS) and time to treatment discontinuation (TTD) for patients with metastatic breast cancer (MBC) using machine learning methods on electronic health records. Patients/methods: Adult females with HR+/HER2- MBC on first- or second-line systemic therapy were eligible. Random survival forest (RSF) models were used to predict optimal regimen classes for individual patients and each line of therapy based on baseline characteristics. Results: RSF models suggested greater use of CDK4 & 6 inhibitor-based therapies may maximize OS and TTD. RSF-predicted optimal treatments demonstrated longer OS and TTD compared with nonoptimal treatments across line of therapy (hazard ratios = 0.44∼0.79). Conclusion: RSF may help inform optimal treatment choices and improve outcomes for patients with HR+/HER2- MBC.

The Effectiveness of a Private Orthopaedic Practice-Based Osteoporosis Management Service to Reduce the Risk of Subsequent Fractures.

BACKGROUND: Osteoporosis is prevalent in the United States, with an increasing need for management. In this study, we evaluated the effectiveness of a private orthopaedic practice-based osteoporosis management service (OP MS) in reducing subsequent fracture risk and improving other aspects of osteoporosis management of patients who had sustained fractures. METHODS: This was a retrospective cohort study using the 100% Medicare data set for Michigan residents with any vertebral; hip, pelvic or femoral; or other nonvertebral fracture during the period of April 1, 2010 to September 30, 2014. Patients who received OP MS care with a follow-up visit within 90 days of the first fracture, and those who did not seek OP MS care but had a physician visit within 90 days of the first fracture, were considered as exposed and unexposed, respectively (first follow-up visit = index date). Eligible patients with continuous enrollment in Medicare Parts A and B for the 90-day pre-index period were followed until the earliest of death, health-plan disenrollment, or study end (December 31, 2014) to evaluate rates of subsequent fracture, osteoporosis medication prescriptions filled, and bone mineral density (BMD) assessments. Health-care costs were evaluated among patients with 12 months of post-index continuous enrollment. Propensity-score matching was used to balance differences in baseline characteristics. Each exposed patient was matched to an unexposed patient within ± 0.01 units of the propensity score. After propensity-score matching, Cox regression examined the hazard ratio (HR) of clinical and economic outcomes in the exposed and unexposed cohorts. RESULTS: Two well-matched cohorts of 1,304 patients each were produced. The exposed cohort had a longer median time to subsequent fracture (998 compared with 743 days; log-rank p = 0.001), a lower risk of subsequent fracture (HR = 0.8; 95% confidence interval [CI] = 0.7 to 0.9), and a higher likelihood of having osteoporosis medication prescriptions filled (HR = 1.7; 95% CI = 1.4 to 2.0) and BMD assessments (HR = 4.3; 95% CI = 3.7 to 5.0). The total 12-month costs ($25,306 compared with $22,896 [USD]; p = 0.082) did not differ significantly between the cohorts. CONCLUSIONS: A private orthopaedic practice-based OP MS effectively reduced subsequent fracture risk, likely through coordinated and ongoing comprehensive patient care, without a significant overall higher cost. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Impact of Proton Pump Inhibitor Use on the Comparative Effectiveness and Safety of Prasugrel Versus Clopidogrel: Insights From the Treatment With Adenosine Diphosphate Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events After Acute Coronary Syndrome (TRANSLATE-ACS) Study.

BACKGROUND: Proton pump inhibitors (PPIs) reduce gastrointestinal bleeding events but may alter clopidogrel metabolism. We sought to understand the comparative effectiveness and safety of prasugrel versus clopidogrel in the context of proton pump inhibitor (PPI) use. METHODS AND RESULTS: Using data on 11 955 acute myocardial infarction (MI) patients treated with percutaneous coronary intervention at 233 hospitals and enrolled in the TRANSLATE-ACS study, we compared whether discharge PPI use altered the association of 1-year adjusted risks of major adverse cardiovascular events (MACE; death, MI, stroke, or unplanned revascularization) and Global Use of Strategies To Open Occluded Arteries (GUSTO) moderate/severe bleeding between prasugrel- and clopidogrel-treated patients. Overall, 17% of prasugrel-treated and 19% of clopidogrel-treated patients received a PPI at hospital discharge. At 1 year, patients discharged on a PPI versus no PPI had higher risks of MACE (adjusted hazard ratio [HR] 1.38, 95% confidence interval [CI] 1.21-1.58) and GUSTO moderate/severe bleeding (adjusted HR 1.55, 95% CI 1.15-2.09). Risk of MACE was similar between prasugrel and clopidogrel regardless of PPI use (adjusted HR 0.88, 95% CI 0.62-1.26 with PPI, adjusted HR 1.07, 95% CI 0.90-1.28 without PPI, interaction P=0.31). Comparative bleeding risk associated with prasugrel versus clopidogrel use differed based on PPI use but did not reach statistical significance (adjusted HR 0.73, 95% CI 0.36-1.48 with PPI, adjusted HR 1.34, 95% CI 0.79-2.27 without PPI, interaction P=0.17). CONCLUSIONS: PPIs did not significantly affect the MACE and bleeding risk associated with prasugrel use, relative to clopidogrel. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01088503.

Comparing Inverse Probability of Treatment Weighting and Instrumental Variable Methods for the Evaluation of Adenosine Diphosphate Receptor Inhibitors After Percutaneous Coronary Intervention.

IMPORTANCE: There is increasing interest in performing comparative effectiveness analyses in large observational databases, yet these analyses must adjust for treatment selection issues. OBJECTIVES: To conduct comparative safety and efficacy analyses of prasugrel vs clopidogrel bisulfate after percutaneous coronary intervention and to evaluate inverse probability of treatment weighting (a propensity score method) and instrumental variable methods. DESIGN, SETTING, AND PARTICIPANTS: This study used data from the Treatment With Adenosine Diphosphate Receptor Inhibitors-Longitudinal Assessment of Treatment Patterns and Events After Acute Coronary Syndrome (TRANSLATE-ACS) study. Included in the study were patients undergoing percutaneous coronary intervention for myocardial infarction, 26.0% of whom received prasugrel. The study dates were April 4, 2010, to October 31, 2012. EXPOSURES: Choice of initial antiplatelet agent (prasugrel or clopidogrel). MAIN OUTCOMES AND MEASURES: Safety and efficacy outcomes included 1-year composite major adverse cardiovascular events, moderate to severe bleeding, and stent thrombosis. Hospitalizations for pneumonia, bone fractures, and planned percutaneous coronary intervention were used as the falsification end points. RESULTS: The study cohort comprised 11 784 participants (mean [SD] age, 60.0 [11.6] years, and 28.0% were female). Using inverse probability of treatment weighting adjustment, prasugrel and clopidogrel had similar major adverse cardiovascular events (hazard ratio [HR], 0.98; 95% CI, 0.83-1.16) and bleeding outcomes (1.18; 0.77-1.80), but prasugrel had a lower rate of stent thrombosis (0.51; 0.31-0.85). Using instrumental variable methods, prasugrel use was associated with a lower rate of the major adverse cardiovascular event end point (HR, 0.68; 95% CI, 0.47-1.00) but nonsignificant differences in the rates of bleeding (0.95; 0.41-2.08) and stent thrombosis (0.67; 0.16-2.00). There was no significant treatment difference noted in any of the falsification end-point rates when analyses were performed using inverse probability of treatment weighting, although the bone fracture end point approached statistical significance. Nevertheless, a lower rate of pneumonia-related hospitalizations was noted in the prasugrel-treated patients when analyses were performed using instrumental variable methods. CONCLUSIONS AND RELEVANCE: Conclusions regarding the safety and efficacy of antiplatelet therapy varied depending on analytic technique, and none were concordant with the results from randomized trials. In addition, both statistical strategies demonstrated concerning associations when tested in the falsification analyses. A high level of scrutiny and careful attention to assumptions and validity are required when interpreting complex analyses of observational data.

Propensity score matching and subclassification in observational studies with multi-level treatments.

In this article, we develop new methods for estimating average treatment effects in observational studies, in settings with more than two treatment levels, assuming unconfoundedness given pretreatment variables. We emphasize propensity score subclassification and matching methods which have been among the most popular methods in the binary treatment literature. Whereas the literature has suggested that these particular propensity-based methods do not naturally extend to the multi-level treatment case, we show, using the concept of weak unconfoundedness and the notion of the generalized propensity score, that adjusting for a scalar function of the pretreatment variables removes all biases associated with observed pretreatment variables. We apply the proposed methods to an analysis of the effect of treatments for fibromyalgia. We also carry out a simulation study to assess the finite sample performance of the methods relative to previously proposed methods.

Direct medical costs and medication compliance among fibromyalgia patients: duloxetine initiators vs. pregabalin initiators.

OBJECTIVES: To assess and compare direct medical costs and medication compliance between patients with fibromyalgia who initiated duloxetine and patients with fibromyalgia who initiated pregabalin in 2008. METHODS: A retrospective cohort study design was used based on a large US national commercial claims database (2006 to 2009). Patients with fibromyalgia aged 18 to 64 who initiated duloxetine or pregabalin in 2008 and who had continuous health insurance 1 year preceding and 1 year following the initiation were selected into duloxetine cohort or pregabalin cohort based on their initiated agent. Medication compliance was measured by total supply days, medication possession ratio (MPR), and proportion of patients with MPR ≥ 0.8. Direct medical costs were measured by annual costs per patient and compared between the cohorts in the year following the initiation. Propensity score stratification and bootstrapping methods were used to adjust for distribution bias, as well as cross-cohort differences in demographic, clinical and economic characteristics, and medication history prior to the initiation. RESULTS: Both the duloxetine (n = 3,033) and pregabalin (n = 4,838) cohorts had a mean initiation age around 49 years, 89% were women. During the postindex year, compared to the pregabalin cohort, the duloxetine cohort had higher totally annual supply days (273.5 vs. 176.6, P < 0.05), higher MPR (0.7 vs. 0.5, P < 0.05), and more patients with MPR ≥ 0.8 (45.1% vs. 29.4%, P < 0.05). Further, relative to pregabalin cohort, duloxetine cohort had lower inpatient costs ($2,994.9 vs. $4,949.6, P < 0.05), lower outpatient costs ($8,259.6 vs. $10,312.2, P < 0.05), similar medication costs ($5,214.6 vs. $5,290.8, P > 0.05), and lower total medical costs ($16,469.1 vs. $20,552.6, P < 0.05) in the postinitiation year. CONCLUSIONS: In a real-world setting, patients with fibromyalgia who initiated duloxetine in 2008 had better medication compliance and consumed less inpatient, outpatient, and total medical costs than those who initiated pregabalin.

Dosing patterns for duloxetine and predictors of high-dose prescriptions in patients with major depressive disorder: analysis from a United States third-party payer perspective.

BACKGROUND: Major depressive disorder (MDD) is a common illness that affects ∼7% of adults in the United States each year. Duloxetine is a dual reuptake inhibitor of serotonin and norepinephrine that has demonstrated efficacy and tolerability in the treatment of MDD. OBJECTIVE: The purpose of our study was to examine dosing patterns and pretreatment predictors of high-dose duloxetine therapy for patients with MDD in the usual clinical setting. METHODS: Data were from 6132 commercially insured patients with MDD initiated on duloxetine during 2005 and 2006. Patients had no duloxetine use in the previous 6 months and had continuous enrollment in a health plan for the 12 months immediately preceding and following initiation. Dosing patterns and predictors of high-dose therapy with duloxetine were examined. RESULTS: Initial doses of duloxetine were <60 mg/d, 60 mg/d, 90 mg/d, and ≥120 mg/d for 32.4%, 60.9%, 3.1%, and 3.5% of patients, respectively. Maximum daily doses were <60 mg, 60 mg, 90 mg, and ≥120 mg for 16.3%, 59.3%, 11.0%, and 13.3% of patients, respectively. Patients treated with >60 mg/d for at least 2 months were older, were more likely to have been treated by a psychiatrist, had greater comorbidity, and had used more health care resources and psychotropic and pain medications in the previous year. The following factors were independently associated with doses of >60 mg/d: older age (odds ratio [OR] = 1.33-1.46); comorbid neuropathic pain (OR = 1.88); fibromyalgia (OR = 1.36); dysthymic disorder (OR = 1.24); prior injury/poisoning (OR = 1.19); physician specialty (psychiatrist, OR = 1.55); and prior use of psychostimulants (OR = 1.26), benzodiazepines (OR = 1.19), venlafaxine (OR = 1.35), or atypical antipsychotics (OR = 1.35). CONCLUSIONS: Most of the commercially insured patients in this dataset were initiated and maintained on a duloxetine dose of 60 mg/d. Although the data are limited in their generalizability, the characteristics associated with higher dose therapy describe a complex group of patients who may require more intensive drug treatment and monitoring.

A provisional screening instrument for four common mental disorders in adult primary care patients.

OBJECTIVE: To develop an adult self-report instrument for provisional diagnosis of four common mental disorders in primary care patients. METHODS: Primary care patients were evaluated during routine clinic visits with a self-report screening tool comprised of 85 DSM-IV symptom-based candidate questions. Patients with a physician-assessed provisional diagnosis for generalized anxiety disorder (GAD), major depressive episode (MDE), past/present mania, and adult attention-deficit/hyperactivity disorder (ADHD), or none of these, completed additional self-report clinical questionnaires, and then were interviewed on the telephone by a trained rater for a SCID/ACDS diagnosis. Responses to the symptom-based candidate questions were used to calculate sensitivity and specificity for a SCID/ACDS diagnosis (GAD, N = 24; MDE, N = 89; Mania, N = 24; ADHD, N = 65) and to select the optimal four questions for each diagnosis to be included in the instrument. RESULTS: Analyses resulted in a 17-item instrument for provisional differential diagnosis of GAD, MDE, past/present mania, and ADHD. Comparison of limited symptom-based versus full DSM-IV criteria-based diagnosis showed minimal differences for relative diagnostic accuracy. Sensitivities and specificities, respectively, were 83% and 75% for GAD, 80% and 80% for MDE, 83% and 82% for mania, and 82%and 73% for ADHD. CONCLUSIONS: Based on this preliminary work, the Provisional Diagnostic Instrument-4 is a brief, easily scored, self-report instrument that may assist primary care physicians to identify potential cases of GAD, MDE, past/present mania, and ADHD.

Does Type of Tumor Histology Impact Survival among Patients with Stage IIIB/IV Non-Small Cell Lung Cancer Treated with First-Line Doublet Chemotherapy?

Chemotherapy regimens may have differential efficacy by histology in nonsmall cell lung cancer (NSCLC). We examined the impact of histology on survival of patients (N = 2,644) with stage IIIB/IV NSCLC who received first-line cisplatin/carboplatin plus gemcitabine (C/C+G) and cisplatin/carboplatin plus a taxane (C/C+T) identified retrospectively in the SEER cancer registry (1997-2002). Patients with squamous and nonsquamous cell carcinoma survived 8.5 months and 8.1 months, respectively (P = .018). No statistically significant difference was observed in survival between C/C+G and C/C+T in both histologies. Adjusting for clinical and demographic characteristics, the effect of treatment regimen on survival did not differ by histology (P for interaction = .257). There was no statistically significant difference in hazard of death by histology in both groups. These results contrast the predictive role of histology and improved survival outcomes observed for cisplatin-pemetrexed regimens in advanced nonsquamous NSCLC.

Neutropenia-related costs in patients treated with first-line chemotherapy for advanced non-small cell lung cancer.

BACKGROUND: Neutropenia is a major adverse event often associated with chemotherapy administration. Neutropenia-related complications often lead to increased use of costly health care including inpatient and outpatient services. Monitoring and treatment of neutropenia thus place an economic burden on the health care system. OBJECTIVES: To evaluate (a) costs and medical resource use for chemotherapy- related afebrile and febrile neutropenia in an elderly population with Stage IIIB or Stage IV non-small cell lung cancer (NSCLC), and (b) costs unrelated to neutropenia and total all-cause health care costs during first-line chemotherapy. METHODS: Study patients in this retrospective database analysis were aged 65 years or older with a diagnosis of Stage IIIB or Stage IV NSCLC in the Surveillance, Epidemiology and End Results (SEER) cancer registry from 1998 through 2002. Neutropenia was identified by the presence of a primary or secondary diagnosis code for diseases of white blood cells (ICD-9-CM = 288.xx) during a period of first-line chemotherapy treatment. Febrile neutropenia was defined by (a) an inpatient hospitalization with a primary or secondary diagnosis for neutropenia occurring at any time during first-line chemotherapy or (b) intravenous or intramuscular antibiotic administration occurring after the initial neutropenia diagnosis and during first-line chemotherapy. Patients with neutropenia without these events were considered to have afebrile neutropenia. Patients were followed in the SEER-Medicare database to evaluate costs (defined as all Medicare payments, primary insurer payments, and patient copayments and deductibles) and resource use associated with afebrile or febrile neutropenia while on first-line chemotherapy. If a patient switched to second-line chemotherapy, the day prior to the switch was defined as the end of first-line treatment. If a switch to second-line therapy did not occur, then first-line therapy was assumed to end 30 days following administration of the last first-line agent. Costs were summed for 2 main types of cost measures: neutropenia-related costs, defined as costs for claims with either a primary or secondary diagnosis of neutropenia, and costs unrelated to neutropenia. Costs were classified using ICD-9-CM diagnosis and procedure codes appearing on the claims, with confidence intervals [CIs] for cost measures estimated by using nonparametric bootstrapping methods. Group comparisons of patient characteristics, medical utilization, and cost study measures were made using 2-sided Pearson chi-square and t-test statistics for categorical and continuous measures, respectively. The no neutropenia group was used as the reference category for comparisons involving patient characteristic, medical utilization, and total all-cause health care cost study measures. For total neutropenia-related costs, afebrile and febrile neutropenia study groups were compared. RESULTS: Among elderly patients treated first-line for advanced NSCLC, 5,138 met inclusion criteria, of whom 1,228 (23.9%) developed afebrile (n = 740, 14.4%) or febrile neutropenia (n = 488, 9.5%) while on first-line chemotherapy. Mean per patient costs for treating neutropenia during first-line chemotherapy were $12,148 (standard deviation [SD] = $15,432, 95% confidence interval [CI] = $10,915-$13,607) for patients with febrile neutropenia and $3,099 (SD = $4,541, 95% CI = $2,796-$3,431) for patients with afebrile neutropenia (P<0.001), with mean (SD) length of follow-up (duration of first-line chemotherapy) of 4.5 (4.8) and 5.5 (7.0) months, respectively. Expressed as a percentage of total all-cause health care costs during first-line chemotherapy, neutropenia-related costs accounted for 32.2% of total costs for patients with febrile neutropenia (mean [SD] = $37,694 [$26,078]) and 9.1% of total costs for patients with afebrile neutropenia (mean [SD] = $34,204 [$26,317]). Mean neutropenia-related costs per patient per month (PPPM) during first-line chemotherapy were $2,700 for patients with febrile neutropenia and $563 for patients with afebrile neutropenia. PPPM costs unrelated to neutropenia for patients with afebrile neutropenia, febrile neutropenia, and no neutropenia, respectively, were $5,655, $5,677, and $6,146. In sensitivity analyses, results were highly sensitive to the definition of neutropenia (i.e., claims with primary diagnosis only vs. primary or secondary diagnosis) but insensitive to the type of chemotherapy regimen. CONCLUSION: Neutropenia is a major adverse event that places patients at an increased risk of infection and subsequent morbidity and mortality. For elderly patients undergoing first-line chemotherapy for NSCLC, neutropenia, particularly febrile neutropenia, is associated with substantially higher total all-cause health care costs.

Cost of antipsychotic polypharmacy in the treatment of schizophrenia.

BACKGROUND: This study compared the costs of antipsychotic polypharmacy for patients who initiated on 1 of the 3 most commonly prescribed atypical antipsychotics - olanzapine, quetiapine, or risperidone. METHODS: Data were drawn from a large, prospective, naturalistic, multi-site, nonrandomized study of treatment for schizophrenia in the United States conducted between July 1997 and September 2003. Participants who were initiated on olanzapine (N = 405), quetiapine (N = 115), or risperidone (N = 276) were followed for 1 year post initiation and compared on: (a) average daily cost of the index antipsychotic while on the index antipsychotic, (b) average daily cost of the coprescribed antipsychotics while on the index antipsychotic, (c) average daily cost of the index antipsychotic and the coprescribed antipsychotics while on the index antipsychotic, (d) total annual cost of antipsychotic medications prescribed in the year following initiation on the index antipsychotic, using propensity score-adjusted bootstrap resampling method. Average daily antipsychotic costs and total annual antipsychotic costs were also estimated using more recent (2004) antipsychotic drug prices. RESULTS: During the 1 year following initiation on the index antipsychotic, the total average daily cost of the index antipsychotic was higher for quetiapine ($15.33) than olanzapine ($13.90, p < .05) and risperidone ($11.04, p < .01), although the average daily cost of the index antipsychotic was higher for olanzapine ($10.08) than risperidone ($6.74, p < .01) or quetiapine ($6.63, p < .01). Lower total average daily costs were observed in risperidone than olanzapine or quetiapine. Significantly lower average daily cost of concomitant antipsychotic medications for olanzapine ($3.82) compared to quetiapine ($8.70, p < .01) or risperidone-initiated patients ($4.30, p < .01) contributed to the lower average daily cost of all antipsychotic medication for olanzapine-initiated patients. Each dollar spent on the index antipsychotic was accompanied by spending an additional $1.31 on concomitant antipsychotics for quetiapine compared to $0.64 for risperidone and $0.38 for olanzapine-initiated patients. A separate intent-to-treat analysis of the total annual antipsychotic cost found a significantly higher total annual antipsychotic cost for quetiapine-initiated patients ($5320) compared to olanzapine ($4536, p < .01) or risperidone ($3813, p < .01). CONCLUSION: Prevalent antipsychotic polypharmacy adds substantial cost to the treatment of schizophrenia. Comparison of medication costs need to address the costs of all antipsychotics. A better understanding of concomitant antipsychotic costs provides a more accurate portrayal of antipsychotic medication costs in the treatment of schizophrenia.