Is primary care ready for a potential new public health emergency in the wake of the COVID-19 pandemic, now subsided?

INTRODUCTION: The lingering burden of the COVID-19 pandemic on primary care clinicians and practices poses a public health emergency for the United States. This study uses clinician-reported data to examine changes in primary care demand and capacity. METHODS: From March 2020 to March 2022, 36 electronic surveys were fielded among primary care clinicians responding to survey invitations as posted on listservs and identified through social media and crowd sourcing. Quantitative and qualitative analyses were performed on both closed- and open-ended survey questions. RESULTS: An average of 937 respondents per survey represented family medicine, pediatrics, internal medicine, geriatrics, and other specialties. Responses reported increases in patient health burden, including worsening chronic care management and increasing volume and complexity. A higher frequency of dental- and eyesight-related issues was noted by respondents, as was a substantial increase in mental or emotional health needs. Respondents also noted increased demand, "record high" wait times, and struggles to keep up with patient needs and the higher volume of patient questions. Frequent qualitative statements highlighted the mismatch of patient needs with practice capacity. Staffing shortages and the inability to fill open clinical positions impaired clinicians' ability to meet patient needs and a substantial proportion of respondents indicated an intention to leave the profession or knew someone who had. CONCLUSION: These data signal an urgent need to take action to support the ability of primary care to meet ongoing patient and population health care needs.

Cost to Medicare of acute kidney injury in percutaneous coronary intervention.

BACKGROUND: Acute kidney injury (AKI), including contrast-induced AKI (CI-AKI), is an important complication of percutaneous coronary intervention (PCI), resulting in short- and long-term adverse clinical outcomes. While prior research has reported an increased cost burden to hospitals from CI-AKI, the incremental cost to payers remains unknown. Understanding this incremental cost may inform decisions and even policy in the future. The objective of this study was to estimate the short- and long-term cost to Medicare of AKI overall, and specifically CI-AKI, in PCI. METHODS: Patients undergoing inpatient PCI between January 2017 and June 2020 were selected from Medicare 100% fee-for-service data. Baseline clinical characteristics, PCI lesion/procedural characteristics, and AKI/CI-AKI during the PCI admission, were identified from diagnosis and procedure codes. Poisson regression, generalized linear modelling, and longitudinal mixed effects modelling, in full and propensity-matched cohorts, were used to compare PCI admission length of stay (LOS) and cost (Medicare paid amount inflated to 2022 US$), as well as total costs during 1-year following PCI, between AKI and non-AKI patients. RESULTS: The study cohort included 509,039 patients, of whom 104,033 (20.4%) were diagnosed with AKI and 9,691 (1.9%) with CI-AKI. In the full cohort, AKI was associated with +4.12 (95% confidence interval = 4.10, 4.15) days index PCI admission LOS, +$11,313 ($11,093, $11,534) index admission costs, and +$14,800 ($14,359, $15,241) total 1-year costs. CI-AKI was associated with +3.03 (2.97, 3.08) days LOS, +$6,566 ($6,148, $6,984) index admission costs, and +$13,381 ($12,118, $14,644) cumulative 1-year costs (all results are adjusted for baseline characteristics). Results from the propensity-matched analyses were similar. CONCLUSIONS: AKI, and specifically CI-AKI, during PCI is associated with significantly longer PCI admission LOS, PCI admission costs, and long-terms costs.

Telemedicine in Primary Care: Lessons Learned About Implementing Health Care Innovations During the COVID-19 Pandemic.

PURPOSE: During the COVID-19 pandemic, telemedicine emerged as an important tool in primary care. Technology and policy-related challenges, however, revealed barriers to adoption and implementation. This report describes the findings from weekly and monthly surveys of primary care clinicians regarding telemedicine during the first 2 years of the pandemic. METHODS: From March 2020 to March 2022, we conducted electronic surveys using convenience samples obtained through social networking and crowdsourcing. Unique tokens were used to confidentially track respondents over time. A multidisciplinary team conducted quantitative and qualitative analyses to identify key concepts and trends. RESULTS: A total of 36 surveys resulted in an average of 937 respondents per survey, representing clinicians from all 50 states and multiple specialties. Initial responses indicated general difficulties in implementing telemedicine due to poor infrastructure and reimbursement mechanisms. Over time, attitudes toward telemedicine improved and respondents considered video and telephone-based care important tools for their practice, though not a replacement for in-person care. CONCLUSIONS: The implementation of telemedicine during COVID-19 identified barriers and opportunities for technology adoption and highlighted steps that could support primary care clinics' ability to learn, adapt, and implement technology.

Lymphedema self-care: economic cost savings and opportunities to improve adherence.

BACKGROUND: Breast cancer-related lymphedema (BCRL) imposes a significant economic burden on patients, providers, and society. There is no curative therapy for BCRL, but management through self-care can reduce symptoms and lower the risk of adverse events. MAIN BODY: The economic burden of BCRL stems from related adverse events, reductions in productivity and employment, and the burden placed on non-medical caregivers. Self-care regimens often include manual lymphatic drainage, compression garments, and meticulous skin care, and may incorporate pneumatic compression devices. These regimens can be effective in managing BCRL, but patients cite inconvenience and interference with daily activities as potential barriers to self-care adherence. As a result, adherence is generally poor and often worsens with time. Because self-care is on-going, poor adherence reduces the effectiveness of regimens and leads to costly treatment of BCRL complications. CONCLUSION: Novel self-care solutions that are more convenient and that interfere less with daily activities could increase self-care adherence and ultimately reduce complication-related costs of BCRL.

The impact of antipsychotic adherence on acute care utilization.

BACKGROUND: Non-adherence to psychotropic medications is common in schizophrenia and bipolar disorders (BDs) leading to adverse outcomes. We examined patterns of antipsychotic use in schizophrenia and BD and their impact on subsequent acute care utilization. METHODS: We used electronic health record (EHR) data of 577 individuals with schizophrenia, 795 with BD, and 618 using antipsychotics without a diagnosis of either illness at two large health systems. We structured three antipsychotics exposure variables: the proportion of days covered (PDC) to measure adherence; medication switch as a new antipsychotic prescription that was different than the initial antipsychotic; and medication stoppage as the lack of an antipsychotic order or fill data in the EHR after the date when the previous supply would have been depleted. Outcome measures included the frequency of inpatient and emergency department (ED) visits up to 12 months after treatment initiation. RESULTS: Approximately half of the study population were adherent to their antipsychotic medication (a PDC ≥ 0.80): 53.6% of those with schizophrenia, 52.4% of those with BD, and 50.3% of those without either diagnosis. Among schizophrenia patients, 22.5% switched medications and 15.1% stopped therapy. Switching and stopping occurred in 15.8% and 15.1% of BD patients and 7.4% and 20.1% of those without either diagnosis, respectively. Across the three cohorts, non-adherence, switching, and stopping therapy were all associated with increased acute care utilization, even after adjusting for baseline demographics, health insurance, past acute care utilization, and comorbidity. CONCLUSION: Non-continuous antipsychotic use is common and associated with high acute care utilization.

Using Agile Science for Rapid Innovation and Implementation of a New Care Model.

As industry consolidation leads to a growing number of large new healthcare delivery networks, patients and their clinicians are losing the important human-centric and relationship-based nature of medical care. The leadership of Hackensack Meridian Health (HMH), a New Jersey-based network of hospitals, research center, and medical school, made an organizational commitment to reverse such loss and restore the social nature of medicine. To attain that goal, HMH engaged both clinicians and administrators to confirm the demand for change, foster a collaborative culture design, and address the unique nature of the individual components in the HMH network. Efforts to transform the HMH care delivery model illustrate the effectiveness of Agile science and its problem-solving methods.

Measuring the Value Functions of Primary Care: Physician-Level Continuity of Care Quality Measure.

PURPOSE: Care continuity is foundational to the clinician/patient relationship; however, little has been done to operationalize continuity of care (CoC) as a clinical quality measure. The American Board of Family Medicine developed the Primary Care CoC clinical quality measure as part of the Measures That Matter to Primary Care initiative. METHODS: Using 12-month Optum Clinformatics Data Mart claims data, we calculated the Bice-Boxerman Continuity of Care Index for each patient, which we rolled up to create an aggregate, physician-level CoC score. The physician quality score is the percent of patients with a Bice-Boxerman Index ≥0.7 (70%). We tested validity in 2 ways. First, we explored the validity of using 0.7 as a threshold for patient CoC within the Optum claims database to validate its use for reflecting patient-level continuity. Second, we explored the validity of the physician CoC measure by examining its association with patient outcomes. We assessed reliability using signal-to-noise methodology. RESULTS: Mean performance on the measure was 27.6%; performance ranged from 0% to 100% (n = 555,213 primary care physicians). Higher levels of CoC were associated with lower levels of care utilization. The measure indicated acceptable levels of validity and reliability. CONCLUSIONS: Continuity is associated with desirable health and cost outcomes as well as patient preference. The CoC clinical quality measure meets validity and reliability requirements for implementation in primary care payment and accountability. Care continuity is important and complementary to access to care, and prioritizing this measure could help shift physician and health system behavior to support continuity.

Comparative Effectiveness of Medical Therapy, Percutaneous Revascularization, and Surgical Coronary Revascularization in Cardiovascular Risk Subgroups of Patients With CKD: A Retrospective Cohort Study of Medicare Beneficiaries.

RATIONALE & OBJECTIVE: Prior studies suggesting that medical therapy is inferior to percutaneous (percutaneous coronary intervention [PCI]) or surgical (coronary artery bypass grafting [CABG]) coronary revascularization in chronic kidney disease (CKD) have not adequately considered medication optimization or baseline cardiovascular risk and have infrequently evaluated progression to kidney failure. We compared, separately, the risks for kidney failure and death after treatment with PCI, CABG, or optimized medical therapy for coronary disease among patients with CKD stratified by cardiovascular disease risk. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 34,385 individuals with CKD identified from a national 20% Medicare sample who underwent angiography or diagnostic stress testing without (low risk) or with (medium risk) prior cardiovascular disease or who presented with acute coronary syndrome (high risk). EXPOSURES: PCI, CABG, or optimized medical therapy (defined by the addition of cardiovascular medications in the absence of coronary revascularization). OUTCOMES: Death, kidney failure, composite outcome of death or kidney failure. ANALYTICAL APPROACH: Adjusted relative rates of death, kidney failure, and the composite of death or kidney failure estimated from Cox proportional hazards models. RESULTS: Among low-risk patients, 960 underwent PCI, 391 underwent CABG, and 6,426 received medical therapy alone; among medium-risk patients, 1,812 underwent PCI, 512 underwent CABG, and 9,984 received medical therapy alone; and among high-risk patients, 4,608 underwent PCI, 1,330 underwent CABG, and 8,362 received medical therapy alone. Among low- and medium-risk patients, neither CABG (HRs of 1.22 [95% CI, 0.96-1.53] and 1.08 [95% CI, 0.91-1.29] for low- and medium-risk patients, respectively) nor PCI (HRs of 1.14 [95% CI, 0.98-1.33] and 1.02 [95% CI, 0.93-1.12], respectively) were associated with reduced mortality compared with medical therapy, but in low-risk patients, CABG was associated with a higher rate of the composite, death or kidney failure (HR, 1.25; 95% CI, 1.02-1.53). In high-risk patients, CABG and PCI were associated with lower mortality (HRs of 0.57 [95% CI, 0.51-0.63] and 0.70 [95% CI, 0.66-0.74], respectively). Also, in high-risk patients, CABG was associated with a higher rate of kidney failure (HR, 1.40; 95% CI, 1.16-1.69). LIMITATIONS: Possible residual confounding; lack of data for coronary angiography or left ventricular ejection fraction; possible differences in decreased kidney function severity between therapy groups. CONCLUSIONS: Outcomes associated with cardiovascular therapies among patients with CKD differed by baseline cardiovascular risk. Coronary revascularization was not associated with improved survival in low-risk patients, but was associated with improved survival in high-risk patients despite a greater observed rate of kidney failure. These findings may inform clinical decision making in the care of patients with both CKD and cardiovascular disease.

ESRD due to Multiple Myeloma in the United States, 2001-2010.

Although management of multiple myeloma has changed substantially in the last decade, it is unknown whether the burden of ESRD due to multiple myeloma has changed, or whether survival of patients with multiple myeloma on RRT has improved. Regarding ESRD due to multiple myeloma necessitating RRT in the United States, we evaluated temporal trends between 2001 and 2010 for demography-adjusted incidence ratios, relative to rates in 2001-2002, and mortality hazards from RRT initiation, relative to hazards in 2001-2002. In this retrospective cohort study, we used the US Renal Data System database (n=1,069,343), 2001-2010, to identify patients with ESRD due to multiple myeloma treated with RRT (n=12,703). Demography-adjusted incidence ratios of ESRD from multiple myeloma decreased between 2001-2002 and 2009-2010 in the overall population (demography-adjusted incidence ratio 0.82; 95% confidence interval, 0.79 to 0.86) and in most demographic subgroups examined. Mortality rates were 86.7, 41.4, and 34.4 per 100 person-years in the first 3 years of RRT, respectively, compared with 32.3, 20.6, and 21.3 in matched controls without multiple myeloma. Unadjusted mortality hazards ratios declined monotonically after 2004 to a value of 0.72; 95% confidence interval, 0.67 to 0.77 in 2009-2010, and declines between 2001-2002 and 2008-2009 were observed (P<0.05) in most demographic subgroups examined. Findings were similar when adjustment was made for demographic characteristics, comorbidity markers, and laboratory test values. These data suggest the incidence of RRT from multiple myeloma in the United States has decreased in the last decade, and clinically meaningful increases in survival have occurred for these patients.

Effects of the prospective payment system on anemia management in maintenance dialysis patients: implications for cost and site of care.

BACKGROUND: The 2011 expanded Prospective Payment System (PPS) and contemporaneous Food and Drug Administration label revision for erythropoiesis-stimulating agents (ESAs) were associated with changes in ESA use and mean hemoglobin levels among patients receiving maintenance dialysis. We aimed to investigate whether these changes coincided with increased red blood cell transfusions or changes to Medicare-incurred costs or sites of anemia management care in the period immediately before and after the introduction of the PPS, 2009-2011. METHODS: From US Medicare end-stage renal disease (ESRD) data (Parts A and B claims), maintenance hemodialysis patients from facilities that initially enrolled 100 % into the ESRD PPS were identified. Dialysis and anemia-related costs per-patient-per-month (PPPM) were calculated at the facility level, and transfusion rates were calculated overall and by site of care (outpatient, inpatient, emergency department, observation stay). RESULTS: More than 4100 facilities were included. Transfusions in both the inpatient and outpatient environments increased. In the inpatient environment, PPPM use increased by 11-17 % per facility in each quarter of 2011 compared with 2009; in the outpatient environment, PPPM use increased overall by 5.0 %. Site of care for transfusions appeared to have shifted. Transfusions occurring in emergency departments or during observation stays increased 13.9 % and 26.4 %, respectively, over 2 years. CONCLUSIONS: Inpatient- and emergency-department-administered transfusions increased, providing some evidence for a partial shift in the cost and site of care for anemia management from dialysis facilities to hospitals. Further exploration into the economic implications of this increase is necessary.

One-year mortality rates in US children with end-stage renal disease.

BACKGROUND/AIMS: Few published data describe survival rates for pediatric end-stage renal disease (ESRD) patients. We aimed to describe one-year mortality rates for US pediatric ESRD patients over a 15-year period. METHODS: In this retrospective cohort study, we used the US Renal Data System database to identify period-prevalent cohorts of patients aged younger than 19 for each year during the period 1995-2010. Yearly cohorts averaged approximately 1,200 maintenance dialysis patients (60% hemodialysis, 40% peritoneal dialysis) and 1,100 transplant recipients. Patients were followed for up to 1 year and censored at change in modality, loss to follow-up, or death. We calculated the unadjusted model-based mortality rates per time at risk, within each cohort year, by treatment modality (hemodialysis, peritoneal dialysis, transplant) and patient characteristics; percentage of deaths by cause; and overall adjusted odds of mortality by characteristics and modality. RESULTS: Approximately 50% of patients were in the age group 15-18, 55% were male, and 45% were female. The most common causes of ESRD were congenital/reflux/obstructive causes (55%) and glomerulonephritis (30%). One-year mortality rates showed evidence of a decrease in the number of peritoneal dialysis patients (6.03 per 100 patient-years, 1995; 2.43, 2010; p = 0.0263). Mortality rates for transplant recipients (average 0.68 per 100 patient-years) were consistently lower than the rates for all dialysis patients (average 4.36 per 100 patient-years). CONCLUSIONS: One-year mortality rates differ by treatment modality in pediatric ESRD patients.

End-stage renal disease attributed to acute tubular necrosis in the United States, 2001-2010.

BACKGROUND/AIMS: Though end-stage renal disease (ESRD) is increasingly attributed to acute tubular necrosis (ATN), contemporary trends in the rates of incidence and recovery of renal function are poorly defined. Hence, we set out to describe the clinical epidemiology of ESRD due to ATN between 2001 and 2010. METHODS: We examined United States Renal Data System data (n = 1,070,490) for 2001 through 2010 to calculate the incidence rates and rates of renal recovery and death for patients with ESRD due to ATN treated with renal replacement therapy (RRT, n = 27,603). RESULTS: Standardized incidence ratios increased between 2001-2002 and 2009-2010 in the overall population (ratio 2.14), having risen in all demographic subgroups examined. Recovery of renal function was more likely in patients with ATN than in matched controls (cumulative incidence 23% vs. 2% at 12 weeks, 34% vs. 4% at 1 year), as was death (cumulative incidence 38% vs. 27% at 1 year). Hazards ratios for renal recovery increased stepwise with year of RRT inception to 1.34 (95% confidence interval 1.24-1.45) for 2009-2010 (vs. 2001-2002). In contrast, hazards ratios for death declined stepwise to 0.83 (0.79-0.87) in 2009-2010. CONCLUSION: While the incidence of ESRD attributed to ATN has increased, prospects of renal recovery and survival have also increased. Despite substantial mortality risk on RRT, renal recovery is not a rare occurrence.

Long-term survival and repeat coronary revascularization in dialysis patients after surgical and percutaneous coronary revascularization with drug-eluting and bare metal stents in the United States.

BACKGROUND: Few published data describe long-term survival of dialysis patients undergoing surgical versus percutaneous coronary revascularization in the era of drug-eluting stents (DES). METHODS AND RESULTS: Using United States Renal Data System data, we identified 23 033 dialysis patients who underwent coronary revascularization (6178 coronary artery bypass grafting, 5011 bare metal stents, 11 844 DES) from 2004 to 2009. Revascularization procedures decreased from 4347 in 2004 to 3344 in 2009. DES use decreased by 41% and bare metal stent use increased by 85% from 2006 to 2007. Long-term survival was estimated by the Kaplan-Meier method, and independent predictors of mortality were examined in a comorbidity-adjusted Cox model. In-hospital mortality for coronary artery bypass grafting patients was 8.2%; all-cause survival at 1, 2, and 5 years was 70%, 57%, and 28%, respectively. In-hospital mortality for DES patients was 2.7%; 1-, 2-, and 5-year survival was 71%, 53%, and 24%, respectively. Independent predictors of mortality were similar in both cohorts: age >65 years, white race, dialysis duration, peritoneal dialysis, and congestive heart failure, but not diabetes mellitus. Survival was significantly higher for coronary artery bypass grafting patients who received internal mammary grafts (hazard ratio, 0.83; P<0.0001). The probability of repeat revascularization accounting for the competing risk of death was 18% with bare metal stents, 19% with DES, and 6% with coronary artery bypass grafting at 1 year. CONCLUSIONS: Among dialysis patients undergoing coronary revascularization, in-hospital mortality was higher after coronary artery bypass grafting, but long-term survival was superior with internal mammary grafts. In-hospital mortality was lower for DES patients, but the probability of repeat revascularization was higher and comparable to that in patients receiving a bare metal stent. Revascularization decisions for dialysis patients should be individualized.

Early mortality in patients starting dialysis appears to go unregistered.

Clinical experience suggests a heightened risk associated with the transition to maintenance dialysis but few national studies have systematically examined early mortality trajectories. Here we calculated weekly mortality rates in the first year of treatment for 498,566 adults initiating maintenance dialysis in the United States (2005-2009). Mortality rates were initially unexpectedly low, peaked at 37.0 per 100 person-years in week 6, and declined steadily to 14.8 by week 51. In both early (weeks 7-12) and later (weeks 13-51) time frames, multivariate mortality associations included older age, female, Caucasian, non-Hispanic ethnicity, end-stage renal disease (ESRD) from hypertension and acute tubular necrosis, ischemic heart disease, estimated glomerular filtration rate of 15 ml/min per 1.73 m(2) or more, shorter duration of nephrologist care, and hemodialysis, especially with a catheter. For early mortality risk, adjusted hazard ratios of 2 or more were seen with age over 65 (5.80 vs. under 40 years), hemodialysis with a catheter (2.73 vs. fistula), and age 40-64 (2.33). For later mortality risk, adjusted hazard ratios of 2 or more were seen with age over 65 (4.32 vs. under 40 years), hemodialysis with a catheter (2.10 vs. fistula), and age 40-64 (2.00). Thus, low initial mortality rates question the accuracy of data collected and are consistent with deaths occurring in the early weeks after starting dialysis not being registered with the United States Renal Data System.

ESRD from autosomal dominant polycystic kidney disease in the United States, 2001-2010.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is amenable to early detection and specialty care. Thus, while important to patients with the condition, end-stage renal disease (ESRD) from ADPKD also may be an indicator of the overall state of nephrology care. STUDY DESIGN: Retrospective cohort study of temporal trends in ESRD from ADPKD and pre-renal replacement therapy (RRT) nephrologist care, 2001-2010 (n = 23,772). SETTING & PARTICIPANTS: US patients who initiated maintenance RRT from 2001 through 2010 (n = 1,069,343) from US Renal Data System data. PREDICTOR: ESRD from ADPKD versus from other causes for baseline characteristics and clinical outcomes; interval 2001-2005 versus 2006-2010 for comparisons of cohort of patients with ESRD from ADPKD. OUTCOMES: Death, wait-listing for kidney transplant, kidney transplantation. MEASUREMENTS: US census data were used as population denominators. Poisson distribution was used to compute incidence rates (IRs). Incidence ratios were standardized to rates in 2001-2002 for age, sex, and race/ethnicity. Patients with and without ADPKD were matched to compare clinical outcomes. Poisson regression was used to calculate IRs and adjusted HRs for clinical events after inception of RRT. RESULTS: General population incidence ratios in 2009-2010 were unchanged from 2001-2002 (incidence ratio, 1.02). Of patients with ADPKD, 48.1% received more than 12 months of nephrology care before RRT; preemptive transplantation was the initial RRT in 14.3% and fistula was the initial hemodialysis access in 35.8%. During 4.9 years of follow-up, patients with ADPKD were more likely to be listed for transplantation (IR, 11.7 [95% CI, 11.5-12.0] vs 8.4 [95% CI, 8.2-8.7] per 100 person-years) and to undergo transplantation (IR, 9.8 [95% CI, 9.5-10.0] vs 4.8 [95% CI, 4.7-5.0] per 100 person-years) and less likely to die (IR, 5.6 [95% CI, 5.4-5.7] vs 15.5 [95% CI, 15.3-15.8] per 100 person-years) than matched controls without ADPKD. LIMITATIONS: Retrospective nonexperimental registry-based study of associations; cause-and-effect relationships cannot be determined. CONCLUSIONS: Although outcomes on dialysis therapy are better for patients with ADPKD than for those without ADPKD, access to predialysis nephrology care and nondeclining ESRD rates may be a cause for concern.

Quantifying a rare disease in administrative data: the example of calciphylaxis.

BACKGROUND: Calciphylaxis, a rare disease seen in chronic dialysis patients, is associated with significant morbidity and mortality. As is the case with other rare diseases, the precise epidemiology of calciphylaxis remains unknown. Absence of a unique International Classification of Diseases (ICD) code impedes its identification in large administrative databases such as the United States Renal Data System (USRDS) and hinders patient-oriented research. This study was designed to develop an algorithm to accurately identify cases of calciphylaxis and to examine its incidence and mortality. DESIGN, PARTICIPANTS, AND MAIN MEASURES: Along with many other diagnoses, calciphylaxis is included in ICD-9 code 275.49, Other Disorders of Calcium Metabolism. Since calciphylaxis is the only disorder listed under this code that requires a skin biopsy for diagnosis, we theorized that simultaneous application of code 275.49 and skin biopsy procedure codes would accurately identify calciphylaxis cases. This novel algorithm was developed using the Partners Research Patient Data Registry (RPDR) (n = 11,451 chronic hemodialysis patients over study period January 2002 to December 2011) using natural language processing and review of medical and pathology records (the gold-standard strategy). We then applied this algorithm to the USRDS to investigate calciphylaxis incidence and mortality. KEY RESULTS: Comparison of our novel research strategy against the gold standard yielded: sensitivity 89.2%, specificity 99.9%, positive likelihood ratio 3,382.3, negative likelihood ratio 0.11, and area under the curve 0.96. Application of the algorithm to the USRDS identified 649 incident calciphylaxis cases over the study period. Although calciphylaxis is rare, its incidence has been increasing, with a major inflection point during 2006-2007, which corresponded with specific addition of calciphylaxis under code 275.49 in October 2006. Calciphylaxis incidence continued to rise even after limiting the study period to 2007 onwards (from 3.7 to 5.7 per 10,000 chronic hemodialysis patients; r = 0.91, p = 0.02). Mortality rates among calciphylaxis patients were noted to be 2.5-3 times higher than average mortality rates for chronic hemodialysis patients. CONCLUSIONS: By developing and successfully applying a novel algorithm, we observed a significant increase in calciphylaxis incidence. Because calciphylaxis is associated with extremely high mortality, our study provides valuable information for future patient-oriented calciphylaxis research, and also serves as a template for investigating other rare diseases.

An approach to addressing selection bias in survival analysis.

This work proposes a frailty model that accounts for non-random treatment assignment in survival analysis. Using Monte Carlo simulation, we found that estimated treatment parameters from our proposed endogenous selection survival model (esSurv) closely parallel the consistent two-stage residual inclusion (2SRI) results, while offering computational and interpretive advantages. The esSurv method greatly enhances computational speed relative to 2SRI by eliminating the need for bootstrapped standard errors and generally results in smaller standard errors than those estimated by 2SRI. In addition, esSurv explicitly estimates the correlation of unobservable factors contributing to both treatment assignment and the outcome of interest, providing an interpretive advantage over the residual parameter estimate in the 2SRI method. Comparisons with commonly used propensity score methods and with a model that does not account for non-random treatment assignment show clear bias in these methods, which is not mitigated by increased sample size. We illustrate using actual dialysis patient data comparing mortality of patients with mature arteriovenous grafts for venous access to mortality of patients with grafts placed but not yet ready for use at the initiation of dialysis. We find strong evidence of endogeneity (with estimate of correlation in unobserved factors ρ^=0.55) and estimate a mature-graft hazard ratio of 0.197 in our proposed method, with a similar 0.173 hazard ratio using 2SRI. The 0.630 hazard ratio from a frailty model without a correction for the non-random nature of treatment assignment illustrates the importance of accounting for endogeneity.

Granulocyte colony-stimulating factor (G-CSF) patterns of use in cancer patients receiving myelosuppressive chemotherapy.

PURPOSE: Febrile neutropenia (FN) is a common and serious complication of myelosuppressive chemotherapy. Guidelines recommend primary granulocyte colony-stimulating factors (G-CSF) prophylaxis (PPG) in patients with a high risk (HR, >20 %) of developing FN. We performed a retrospective analysis using a subset of the Medicare 5 % database to assess patterns of G-CSF use and FN occurrence among elderly cancer patients receiving myelosuppressive chemotherapy. METHODS: Chemotherapy courses for patients aged 65+ years were identified; only the first course was used for this analysis. Using clinical guidelines, chemotherapy regimens were classified as HR or intermediate risk (IR) for FN. The first administration of G-CSF was classified as either PPG (within the first 5 days of the first cycle), secondary prophylaxis, or reactive. RESULTS: Twelve thousand seven hundred seven courses across five tumor types were classified as having a HR or IR regimen. G-CSF was used in 24.5-73.8 % of patients receiving a HR FN regimen, with the highest use in breast cancer or NHL. Except for breast cancer (where PPG was used in 52.1 %), PPG was given in less than half of patients receiving a HR regimen. Depending on the tumor type, 4.8-22.6 % of patients with a HR regimen had a neutropenia-related hospitalization. CONCLUSIONS: Guidelines recommend PPG with HR FN regimens and older age (>65 years), an important risk factor for developing severe neutropenic complications. However, our results show that in this elderly population, PPG was not routinely used (range 4.8-52.1 %) in patients receiving HR FN regimens. Careful attention to FN risk factors, including chemotherapy regimen and patient age, is needed when planning treatment strategies.