Optical bistability modulation based on graphene sandwich structure with topological interface modes.

In this paper, we have investigated optical bistability modulation of transmitted beam that can be achieved by graphene sandwich structure with topological interface modes at terahertz frequency. Graphene with strong nonlinear optical effect was combined with sandwich photonic crystal to form a new sandwich structure with topological interface modes. The light-limiting properties of the topological interface modes, as well as its high unidirectionality and high transmission efficiency, all contribute positively to the reduction of the optical bistability threshold. In addition, the topological interface modes can effectively ensure the stability of the two steady state switching in the case of external interference. Moreover, optical bistability is closely related to the incident angle, the Fermi energy, the relaxation time, and the number of layers of graphene. Through parameter optimization, optical bistability with threshold of 105 V/m can be obtained, which has reached or is close to the range of the weak field.

Tunable optical differential operation based on graphene at a telecommunication wavelength.

Optical differential operation based on the photonic spin Hall effect(SHE) has attracted extensive attention in image processing of edge detection, which has advantages of high speed, parallelism, and low power consumption. Here, we theoretically demonstrate tunable optical differential operation in a four-layered nanostructure of prism-graphene-air gap-substrate. It is shown that the spatial differentiation arises inherently from the photonic SHE. Furthermore, we find that the transverse spin-Hall shift induced by the photonic SHE changes dramatically near the Brewster angle with the incident angle increases at a telecommunication wavelength. Meanwhile, the Fermi energy of graphene and the thickness of the air gap can affect the transverse spin shift. Interestingly, we can easily adjust the Fermi energy of graphene in real time through external electrostatic field biasing, enabling fast edge imaging switching at a telecommunication wavelength. This may provide a potential way for future tunable spin-photonic devices, and open up more possible applications for artificial intelligence, such as target recognition, biomedical imaging, and edge detection.

Optical bistability in a heterodimer composed of a quantum dot and a metallic nanoshell.

We theoretically explore the conditions for generating optical bistability (OB) in a heterodimer comprised of a semiconductor quantum dot (SQD) and a metallic nanoshell (MNS). The MNS is made of a metallic nanosphere as a core and a dielectric material as a shell. For the specific hybrid system considered, the bistable effect appears only if the frequency of the pump field is equal to (or slightly less than) the exciton frequency for a proper shell thickness. Bistability phase diagrams, when plotted, show that the dipole-induced bistable region can be greatly broadened by changing the shell thickness of the MNS in a strong exciton-plasmon coupling regime. In particular, we demonstrate that the multipole polarization not only narrows the bistable zone but also enlarges the corresponding thresholds for a given intermediate scaled pumping intensity. On the other hand, when the SQD couples strongly with the MNS, the multipole polarization can also significantly broaden the bistable region and induce a great suppression of the FWM (four-wave mixing) signal for a fixed shell thickness. These interesting findings offer a fresh understanding of the bistability conditions in an SQD/MNS heterodimer, and may be useful in the fabrication of high-performance and low-threshold optical bistable nanodevices.

Risk of malignant melanoma and non-melanoma skin cancer in rheumatoid arthritis patients initiating methotrexate versus hydroxychloroquine: a cohort study.

OBJECTIVES: To characterise the incidence rate of skin cancer associated with methotrexate and hydroxychloroquine in older adults with rheumatoid arthritis (RA). METHODS: RA patients aged ≥65 years who initiated methotrexate or hydroxychloroquine as their first disease modifying antirheumatic drugs (DMARDs). The primary outcome was new occurrence of any skin cancer (i.e. malignant melanoma or non-melanoma skin cancer; NMSC) based on validated algorithms (positive predictive value >83%). Secondary outcomes were malignant melanoma, NMSC, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC). We estimated the incidence rates (IRs) and hazard ratios (HRs) for each outcome in the 1:1 propensity score (PS)-matched methotrexate and hydroxychloroquine groups. RESULTS: We included 24,577 PS-matched pairs of methotrexate and hydroxychloroquine initiators. Compared with hydroxychloroquine (IR 25.20/1,000 person-years), methotrexate initiators (IR 26.21/1,000 person-years) had a similar risk of any skin cancer [HR 1.03 -(95%CI 0.92, 1.14)] over a mean follow-up of 388 days. The HR (95%CI) associated with methotrexate was 1.39 (0.87, 2.21) for malignant melanoma, 1.01(0.90, 1.12) for NMSC, 1.37 (1.13, 1.66) for BCC, and 0.79 (0.63, 0.99) for SCC compared with hydroxychloroquine. CONCLUSIONS: In this large cohort of older RA patients initiating methotrexate or hydroxychloroquine as their first DMARD, we found no difference in the risk of skin cancer including malignant melanoma and NMSC. However, for specific components of NMSC, methotrexate initiators had higher risk of BCC but lower risk of SCC compared with hydroxychloroquine initiators.

Cardiovascular Risks of Hydroxychloroquine vs Methotrexate in Patients With Rheumatoid Arthritis.

BACKGROUND: Hydroxychloroquine is often used as a first-line treatment of rheumatoid arthritis despite limited evidence on its cardiovascular risk. OBJECTIVES: We conducted a cardiovascular safety evaluation comparing hydroxychloroquine to methotrexate among patients with rheumatoid arthritis. METHODS: Using Medicare data (2008-2016), we identified 54,462 propensity score-matched patients with rheumatoid arthritis, aged ≥65 years, who initiated hydroxychloroquine or methotrexate. Primary outcomes were sudden cardiac arrest or ventricular arrythmia (SCA/VA) and major adverse cardiovascular event (MACE). Secondary outcomes were cardiovascular mortality, all-cause mortality, myocardial infarction, stroke, and hospitalized heart failure (HF). We also examined treatment effect modification by history of HF. RESULTS: Hydroxychloroquine was not associated with risk of SCA/VA (HR: 1.03; 95% CI: 0.79-1.35) or MACE (HR: 1.07; 95% CI: 0.97-1.18) compared with methotrexate. In patients with history of HF, hydroxychloroquine initiators had a higher risk of MACE (HR: 1.30; 95% CI: 1.08-1.56), cardiovascular mortality (HR: 1.34; 95% CI: 1.06-1.70), all-cause mortality (HR: 1.22; 95% CI: 1.04-1.43), myocardial infarction (HR: 1.74; 95% CI: 1.25-2.42), and hospitalized HF (HR: 1.29; 95% CI: 1.07-1.54) compared to methotrexate initiators. Cardiovascular risks were not different in patients without history of HF except for an increased hospitalized HF risk (HR: 1.57; 95% CI: 1.30-1.90) among hydroxychloroquine initiators. CONCLUSIONS: In older patients with rheumatoid arthritis, hydroxychloroquine and methotrexate showed similar SCA/VA and MACE risks; however, hydroxychloroquine initiators with history of HF had higher risks of MACE, cardiovascular mortality, all-cause mortality, and myocardial infarction. An increased hospitalized HF risk was observed among hydroxychloroquine initiators regardless of an HF history.

Ultra-strong optical four-wave mixing signal induced by strong exciton-phonon and exciton-plasmon couplings.

We propose a scheme to generate ultra-strong four-wave mixing (FWM) signal based on a suspended monolayer graphene nanoribbon nanomechanical resonator (NR) coupled to an Au nanoparticle (NP). It is shown that, the FWM spectrum can switch among two-peaked, three-peaked, four-peaked or five-peaked via the modulation of exciton-phonon and exciton-plasmon couplings. This is mainly attributed to the vibrational properties of NR related to the exciton-phonon coupling, and the energy-level splitting of the localized exciton correlated to three classes of resonances consisting of three-photon resonance, Rayleigh Resonance, and AC-Stark atomic resonance. Especially, in a dual-strong coupling regime, the gains for these peaks can be as high as nine orders of magnitude (∼ 109) around the lower bistable threshold due to a combined effect of two couplings. Our findings not only offer an efficient way to measure the vibrational frequency of NR and the exciton-phonon coupling strength but also provide a possibility to fabricate high-performance optoelectronic nanodevices.

Prevalence of Avoidable and Bias-Inflicting Methodological Pitfalls in Real-World Studies of Medication Safety and Effectiveness.

Many real-word evidence (RWE) studies that utilize existing healthcare data to evaluate treatment effects incur substantial but avoidable bias from methodologically flawed study design; however, the extent of preventable methodological pitfalls in current RWE is unknown. To characterize the prevalence of avoidable methodological pitfalls with potential for bias in published claims-based studies of medication safety or effectiveness, we conducted an English-language search of PubMed for articles published from January 1, 2010 to May 20, 2019 and randomly selected 75 studies (10 case-control and 65 cohort studies) that evaluated safety or effectiveness of cardiovascular, diabetes, or osteoporosis medications using US health insurance claims. General and methodological study characteristics were extracted independently by two reviewers, and potential for bias was assessed across nine bias domains. Nearly all studies (95%) had at least one avoidable methodological issue known to incur bias, and 81% had potentially at least one of the four issues considered major due to their potential to undermine study validity: time-related bias (57%), potential for depletion of outcome-susceptible individuals (44%), inappropriate adjustment for postbaseline variables (41%), or potential for reverse causation (39%). The median number of major issues per study was 2 (interquartile range (IQR), 1-3) and was lower in cohort studies with a new-user, active-comparator design (median 1, IQR 0-1) than in cohort studies of prevalent users with a nonuser comparator (median 3, IQR 3-4). Recognizing and avoiding known methodological study design pitfalls could substantially improve the utility of RWE and confidence in its validity.

Risk of venous thromboembolism associated with methotrexate versus hydroxychloroquine for rheumatoid arthritis: A propensity score-matched cohort study.

AIMS: Patients with rheumatoid arthritis (RA) have an increased risk of venous thromboembolism (VTE), likely related to underlying inflammation. We examined VTE risk associated with two commonly used immunomodulators in RA patients, methotrexate and hydroxychloroquine. METHODS AND RESULTS: Using U.S. Medicare claims data (2008-2017), we identified RA patients (≥65 years) who initiated methotrexate or hydroxychloroquine without prior use of any immunomodulators. The primary outcome was VTE, a composite of pulmonary embolism (PE) or deep vein thrombosis (DVT). Secondary outcomes included PE, DVT, and all-cause mortality. After 1:1 propensity score matching for confounding control, we identified 26,534 pairs of methotrexate and hydroxychloroquine initiators (mean (SD) age 74 (7) years; 79% female). During a total of 56,686 person-years of follow-up, 208 methotrexate and 83 hydroxychloroquine initiators developed VTE. The incidence rate of VTE was higher among methotrexate initiators (6.94/1,000 person-years) than hydroxychloroquine initiators (3.11/1,000 person-years) with a hazard ratio (HR) of 2.26 (95% CI 1.75, 2.91). Methotrexate initiators had a greater risk of PE (HR 3.30, 95% CI 2.28, 4.77) and DVT (HR 1.53, 95% CI 1.07, 2.19) than hydroxychloroquine initiators. All-cause mortality was similar between the two groups (HR 0.91, 95% CI 0.83, 1.00). CONCLUSION: In this large real-world cohort of older RA patients, treatment with methotrexate was associated with a 2-fold increased risk of VTE relative to hydroxychloroquine, although all-cause mortality was similar. Future experimental studies with non-user control groups are needed to determine the causal relationships between the study drugs and VTE and whether methotrexate elevates or hydroxychloroquine reduces the risk of VTE.

Impact of implementing electronic prior authorization on medication filling in an electronic health record system in a large healthcare system.

OBJECTIVE: Medications frequently require prior authorization from payers before filling is authorized. Obtaining prior authorization can create delays in filling prescriptions and ultimately reduce patient adherence to medication. Electronic prior authorization (ePA), embedded in the electronic health record (EHR), could remove some barriers but has not been rigorously evaluated. We sought to evaluate the impact of implementing an ePA system on prescription filling. MATERIALS AND METHODS: ePA was implemented in 2 phases in September and November 2018 in a large US healthcare system. This staggered implementation enabled the later-implementing sites to be controls. Using EHR data from all prescriptions written and linked information on whether prescriptions were filled at pharmacies, we 1:1 matched ePA prescriptions with non-ePA prescriptions for the same insurance plan, medication, and site, before and after ePA implementation, to evaluate primary adherence, or the proportion of prescriptions filled within 30 days, using generalized estimating equations. We also conducted concurrent analyses across sites during the peri-implementation period (Sept-Oct 2018). RESULTS: Of 74 546 eligible ePA prescriptions, 38 851 were matched with preimplementation controls. In total, 24 930 (64.2%) ePA prescriptions were filled compared with 26 731 (68.8%) control prescriptions (Adjusted Relative Risk [aRR]: 0.92, 95%CI: 0.91-0.93). Concurrent analyses revealed similar findings (64.7% for ePA vs 62.3% control prescriptions, aRR: 1.03, 95%CI: 0.98-1.09). DISCUSSION: Challenges with implementation, such as misfiring and insurance fragmentation, could have undermined its effectiveness, providing implications for other health informatics interventions deployed in outpatient care. CONCLUSION: Despite increasing interest in implementing ePA to improve prescription filling, adoption did not change medication adherence.

Comparative Risk of Nonvertebral Fractures Among Patients With Rheumatoid Arthritis Treated With Biologic or Targeted Synthetic Disease-Modifying Antirheumatic Drugs.

OBJECTIVE: The objective of this study was to compare the incidence rate of nonvertebral osteoporotic fractures (NVFs) in patients with rheumatoid arthritis (RA) initiating one of the nine biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs). METHODS: We analyzed claims data from Optum (2008 to March 2019), Medicare, and MarketScan (2008-2017) to identify adults with RA who newly initiated b/tsDMARDs. Adalimumab was the most frequently used and was thus selected as a reference. The primary outcome was a composite of incident NVFs, including hip, humerus, pelvis, and wrist fractures, based on validated algorithms. We adjusted for greater than 70 potential confounders in each database through propensity score-based inverse probability treatment weighting. Follow-up time started the day after cohort entry until the first occurrence of one of the following: outcome, treatment discontinuation, switching, nursing home admission, death, disenrollment, or end of study period. For each drug comparison, weighted Cox proportional hazards models estimated the hazard ratios (HRs) and 95% confidence intervals (CIs). Secondary analyses were conducted in patients switching from a tumor necrosis factor inhibitor to a different b/tsDMARD. RESULTS: A total of 134,693 b/tsDMARD initiators were identified across three databases. The adjusted HRs showed similar risk of composite NVFs in all b/tsDMARD exposures compared with adalimumab: abatacept, HR 1.03 (95% CI 0.82-1.30); certolizumab, HR 1.08 (95% CI 0.79-1.49); etanercept, HR 1.12 (95% CI 0.89-1.40); golimumab, HR 0.91 (95% CI 0.59-1.39); infliximab, HR 1.03 (95% CI 0.84-1.28); rituximab, HR 1.07 (95% CI 0.74-1.55); tocilizumab, HR 1.24 (95% CI 0.71-2.17); and tofacitinib, HR 1.07 (95% CI 0.69-1.64). Secondary analyses showed similar results. CONCLUSION: This multidatabase cohort study found no differences in the risk of NVFs across individual b/tsDMARDs for RA, which provides reassurance to physicians prescribing b/tsDMARDs, especially to patients at high risk of developing NVFs.

Validation of claims-based algorithms to identify patients with psoriasis.

PURPOSE: Accurately identifying patients with psoriasis (PsO) is crucial for generating real-world evidence on PsO disease course and treatment utilization. METHODS: We developed nine claims-based algorithms for PsO using a combination of the International Classification of Diseases (ICD)-9 codes, specialist visit, and medication dispensing using Medicare linked to electronic health records data (2013-2014) in two healthcare provider networks in Boston, Massachusetts. We calculated positive predictive value (PPV) and 95% confidence interval (CI) for each algorithm using the treating physician's diagnosis of PsO via chart review as the gold standard. Among the confirmed PsO cases, we assessed their PsO disease activity. RESULTS: The nine claims-based algorithms identified 990 unique patient records. Of those, 918 (92.7%) with adequate information were reviewed. The PPV of the algorithms ranged from 65.1 to 82.9%. An algorithm defined as ≥1 ICD-9 diagnosis code for PsO and ≥1 prescription claim for topical vitamin D agents showed the highest PPV (82.9%). The PPV of the algorithm requiring ≥2 ICD-9 diagnosis codes and ≥1 prescription claim for PsO treatment excluding topical steroids was 81.1% but higher (82.5%) when ≥1 diagnosis was from a dermatologist. Among 411 PsO patients with adequate information on PsO disease activity in EHRs, 1.5-5.8% had no disease activity, 31.3-36.8% mild, and 26.9-35.1% moderate-to-severe across the algorithms. CONCLUSIONS: Claims-based algorithms based on a combination of PsO diagnosis codes and dispensing for PsO-specific treatments had a moderate-to-high PPV. These algorithms can serve as a useful tool to identify patients with PsO in future real-world data pharmacoepidemiologic studies.

Changes in Erythropoiesis Stimulating Agent Use Under a Risk Evaluation and Mitigation Strategy (REMS) Program.

INTRODUCTION: Risk evaluation and mitigation strategy (REMS) programs are intended to improve safe use of US Food and Drug Administration-approved drugs. However, controversy exists over whether they consistently accomplish this goal. OBJECTIVE: We aimed to assess how initiation of the erythropoiesis stimulating agents (ESAs) darbepoetin alfa and epoetin alfa changed following implementation and enforcement (following a 1-year post-implementation grace period) of a prominent REMS program warning physicians against use in cancer patients with hemoglobin above 10 g/dL. METHODS: Using claims data from a large US commercial insurance company, we conducted interrupted time-series analyses of darbepoetin alfa and epoetin alfa initiation among adult cancer patients in the 12 months before REMS program implementation, after REMS program implementation, and after REMS program enforcement. We also evaluated differences in inappropriate initiation (hemoglobin tests all above 10 g/dL in the prior month) between the periods. RESULTS: In total, we identified 3456 darbepoetin alfa initiators and 2632 epoetin alfa initiators. Over the study period, the monthly number of initiators per 100,000 patients with cancer fell from 119 to 32 for darbepoetin alfa and from 82 to 34 for epoetin alfa. However, non-significant post-REMS program implementation level and slope changes per 100,000 adult patients with cancer were observed for darbepoetin alfa (level 0.03 [95% confidence interval (CI) -14.98 to 15.05]; slope 1.94 [95% CI -0.22 to 4.10]) and epoetin alfa (level -4.10 [95% CI -16.85 to 8.65]; slope -0.52 [95% CI -2.35 to 1.32]). Non-significant post-REMS program enforcement level and slope changes were also seen for both drugs (darbepoetin alfa level 1.58 [95% CI -0.58 to 3.74, slope -0.28 [95% CI -15.29 to 14.73]; epoetin alfa level 1.58 (95% CI -0.26 to 3.42], slope 5.74 [95% CI -7.01 to 18.49]). Finally, non-significant changes in inappropriate darbepoetin alfa (60% vs. 53% vs. 57%, p = 0.68) and epoetin alfa (53% vs. 53% vs. 46%, p = 0.41) initiation were observed between the three study periods. CONCLUSION: REMS program implementation and enforcement were not associated with significant changes in ESA initiation, adding to concerns over the degree to which certain REMS programs enhance patient safety.

Association Between Congenital Cytomegalovirus and the Prevalence at Birth of Microcephaly in the United States.

Importance: Congenital cytomegalovirus (cCMV) has received far less clinical and public health attention as a teratogenic infection than the Zika virus epidemic. However, cCMV may be responsible for a large fraction of microcephaly cases in the United States. Objective: To evaluate the association between cCMV and the prevalence at birth of microcephaly in the United States. Design, Setting, and Participants: This population-based cohort study included pregnant women and their newborns identified in 2 insurance claims databases from the United States: Medicaid Analytic eXtract (January 1, 2000, to December 31, 2013) and IBM Research MarketScan, a database for employer-sponsored private health insurance (January 1, 2011, to September 30, 2015). All pregnancies that resulted in live births in women with full health benefits were included. Analysis began June 2016 and ended May 2020. Exposures: Congenital cytomegalovirus infection documented in inpatient or outpatient newborn claims records. Main Outcomes and Measures: The primary outcome was microcephaly at birth documented in inpatient or outpatient newborn and/or maternal claims records. Cases with chromosomal abnormalities or neural tube defects were excluded. The association between cCMV and microcephaly was estimated in the pooled cohort using prevalence ratios (PRs) and 95% CIs. Results: In the pooled cohort of 2 338 580 pregnancies (2 075 410 pregnancies [88.7%] were among women younger than 35 years), 336 infants (0.014%) had a cCMV diagnosis. The prevalence of microcephaly among newborns with and without a cCMV diagnosis was 655 and 2.8 per 10 000 live births, respectively (PR, 232; 95% CI, 154-350). After restricting to CMV-tested newborns (572 [0.024%]) to correct for preferential testing of infants with microcephaly, the PR was 15 (95% CI, 5.2-41). However, this PR is biased if other cCMV-related outcomes (eg, hearing loss) trigger testing because cCMV prevalence in tested infants, with ([46%]) or without microcephaly (22 of 559 [3.9%]), would overestimate that in the source population. Therefore, the prevalence of cCMV in overall infants with microcephaly (22 of 669 [3.2%]) was compared with that from an external unbiased sample of US infants screened at birth (449 of 100 332 [0.45%]) to estimate a PR of 7.4 (95% CI, 4.8-11.5) as a conservative lower bound. Conclusions and Relevance: Congenital cytomegalovirus infection increases the prevalence of microcephaly at birth by at least 7-fold. Prevention of CMV infection during pregnancy might substantially reduce the number of newborns with microcephaly and other cCMV-related outcomes in the United States.

Dual-channel bistable switch based on a monolayer graphene nanoribbon nanoresonator coupled to a metal nanoparticle.

We theoretically propose a dual-channel bistable switch based on a monolayer Z-shaped graphene nanoribbon nanoresonator (NR) coupled to a metal nanoparticle (MNP). We show that the bistable nonlinear absorption response can be realized due to a competition and combination of the exciton-plasmon and exciton-phonon interactions. We map out two-dimensional and three-dimensional bistability phase diagrams, which reveal clearly the dynamical evolution of the roles played by these two interactions in managing optical bistability (OB) at all stages. Specifically, the bistable switch proposed can be controlled via a single channel or dual channels by only adjusting the intensity or frequency of the pump field. In/outside these channels, the switch will be turned on/off. The results obtained here not only can be employed to measure precisely the distance between the MNP and the NR but also provide promising applications in optical switching and optical storage.

Validation of algorithms to identify adverse perinatal outcomes in the Medicaid Analytic Extract database.

BACKGROUND: The Medicaid Analytic eXtract (MAX) is a health care utilization database from publicly insured individuals that has been used for studies of drug safety in pregnancy. Claims-based algorithms for defining many important maternal and neonatal outcomes have not been validated. OBJECTIVE: To validate claims-based algorithms for identifying selected pregnancy outcomes in MAX using hospital medical records. METHODS: The medical records of mothers who delivered between 2000 and 2010 within a single large healthcare system were linked to their claims in MAX. Claims-based algorithms for placental abruption, preeclampsia, postpartum hemorrhage, small for gestational age, and noncardiac congenital malformation were defined. Fifty randomly sampled cases for each outcome identified using these algorithms were selected, and their medical records were independently reviewed by two physicians to confirm the presence of the diagnosis of interest; disagreements were resolved by a third physician reviewer. Positive predictive values (PPVs) and 95% confidence intervals (CIs) of the claims-based algorithms were calculated using medical records as the gold standard. RESULTS: The linked cohort included 10,899 live-birth pregnancies. The PPV was 92% (95% CI, 82%-97%) for placental abruption, 82% (95% CI, 70%-91%) for preeclampsia, 74% (95% CI, 61%-85%) for postpartum hemorrhage, 92% (95% CI, 82%-97%) for small for gestational age, and 86% (95% CI, 74%-94%) for noncardiac congenital malformation. CONCLUSIONS: Across the perinatal outcomes considered, PPVs ranged between 74% and 92%. These PPVs can inform bias analyses that correct for outcome misclassification.

Mapping from the International Classification of Diseases (ICD) 9th to 10th Revision for Research in Biologics and Biosimilars Using Administrative Healthcare Data.

PURPOSE: The Centers for Medicare and Medicaid Services (CMS) mandated the transition from ICD-9 to ICD-10 codes on October 1, 2015. Postmarketing surveillance of newly marketed drugs, including novel biologics and biosimilars, requires a robust approach to convert ICD-9 to ICD-10 codes for study variables. We examined three mapping methods for health conditions (HCs) of interest to the Biologics and Biosimilars Collective Intelligence Consortium (BBCIC) and compared their prevalence. METHODS: Using CMS General Equivalence Mappings, we applied forward-backward mapping (FBM) to 108 HCs and secondary mapping (SM) and tertiary mapping (TM) to seven preselected HCs. A physician reviewed the mapped ICD-10 codes. The prevalence of the 108 HCs defined by ICD-9 versus ICD-10 codes was examined in BBCIC's distributed research network (September 1, 2012 to March 31, 2018). We visually assessed prevalence trends of these HCs and applied a threshold of 20% level change in ICD-9 versus ICD-10 prevalence. RESULTS: Nearly four times more ICD-10 codes were mapped by SM and TM than FBM, but most were irrelevant or nonspecific. For conditions like myocardial infarction, SM or TM did not generate additional ICD-10 codes. Through visual inspection, one-fifth of the HCs had inconsistent ICD-9 versus ICD-10 prevalence trends. 13% of HCs had a level change greater than +/-20%. CONCLUSION: FBM is generally the most efficient way to convert ICD-9 to ICD-10 codes, yet manual review of converted ICD-10 codes is recommended even for FBM. The lack of existing guidance to compare the performance of ICD-9 with ICD-10 codes led to challenges in empirically determining the quality of conversions.

Glucose-lowering medications and the risk of cancer: A methodological review of studies based on real-world data.

AIM: To review the methodology of observational studies examining the association between glucose-lowering medications and cancer to identify the most common methodological challenges and sources of bias. METHODS: We searched PubMed systematically to identify observational studies on glucose-lowering medications and cancer published between January 2000 and January 2016. We assessed the design and analytical methods used in each study, with a focus on their ability to achieve study validity, and further evaluated the prevalence of major methodological choices over time. RESULTS: Of 155 studies evaluated, only 26% implemented a new-user design, 41% used an active comparator, 33% implemented a lag or latency period, and 51% adjusted for diabetes duration. Potential for immortal person-time bias was identified in 63% of the studies; 55% of the studies adjusted for variables measured during the follow-up without appropriate statistical methods. Aside from a decreasing trend in adjusting for variables measured during the follow-up, we observed no trends in methodological choices over time. CONCLUSIONS: The prevalence of well-known design and analysis flaws that may lead to biased results remains high among observational studies on glucose-lowering medications and cancer, limiting the conclusions that can be drawn from these studies. Avoiding known pitfalls could substantially improve the quality and validity of real-world evidence in this field.