A SAS program for calculating cumulative incidence of events (with confidence limits) and number at risk at specified time intervals with partially censored data

Epidemiology of traumatic brain injury-associated epilepsy and early use of anti-epilepsy drugs: An analysis of insurance claims data, 2004-2014

BACKGROUND

About 2.8 million TBI-related emergency department visits, hospitalizations and deaths occurred in 2013 in the United States. Post-traumatic epilepsy (PTE) can be a disabling, life-long outcome of TBI.

OBJECTIVES

The purpose of this study is to address the probability of developing PTE within 9 years after TBI, the risk factors associated with PTE, the prevalence of anti-epileptic drug (AEDs) use, and the effectiveness of using AEDs prophylactically after TBI to prevent the development of PTE.

METHODS

Using MarketScan® databases covering commercial, Medicare Supplemental, and multi-state Medicaid enrollees from 2004 to 2014, we examined the incidence of early seizures (within seven days after TBI) and cumulative incidence of PTE, the hazard ratios (HR) of PTE by age, gender, TBI severity, early seizure and AED use (carbamazepine, clonazepam, divalproex sodium, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, phenytoin, pregabalin, topiramate, acetazolamide). We used backward selection to build the final Cox proportional hazard model and conducted multivariable survival analysis to obtain estimates of crude and adjusted HR (cHRs, aHRs) of PTE and 95% confidence intervals (CI).

RESULTS

The incidence of early seizure among TBI patients in our study was 0.5%. The cumulative incidence of PTE increased from 1.0% in one year to 4.0% in nine years. Most patients with TBI (93%) were not prescribed any AED. Gender was not associated with PTE. The risk of PTE was higher for individuals with older age, early seizures, and more severe TBI. Only individuals using prophylactic acetazolamide had significantly lower risk of PTE (aHR = 0.6, CI 0.4-0.9) compared to those not using any AED.

CONCLUSION

The probability of developing PTE increased within the study period. The risk of developing PTE significantly increased with age, early seizure and TBI severity. Most of the individuals did not receive AED after TBI. There was no evidence suggesting AEDs helped to prevent PTE with the possible exception of acetazolamide. However, further studies may be needed to test the efficacy of acetazolamide in preventing PTE.

Neutrophil-lymphocyte ratio, gamma-glutamyl transpeptidase, lipase, high-density lipoprotein as a panel of factors to predict acute pancreatitis in pregnancy

Acute pancreatitis in pregnancy (APIP) is a rare but dangerous complication. APIP has common symptoms with acute abdomen. Assessment of an acute abdomen is more complicated during pregnancy because the gravid uterus could mask most of symptomatic signs. It has been a challenge to diagnose APIP by physical examination or diagnostic imaging. Case studies on APIP are also limited for analysis on the risk factors associated with the disease. This retrospective study evaluated a series of risk factors from a relatively substantial number of APIP cases to determine early predictors or prognosis markers for APIP.Fifty-nine APIP patients together with 179 random normal pregnant women in Shengjing Affiliated Hospital of China Medical University were included for this retrospective study. Medical parameters of blood test in biochemistry and hematology were compared between 2 groups using t test. Multivariate logistic regression analysis was performed to investigate the relationship between various factors and APIP using Statistical Applied Software (SAS student version).Compared with normal pregnant women, APIP patients have elevated values in alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen, creatinine, C-reactive protein, direct bilirubin, fibrin degradation products, gamma-glutamyl transpeptidase (GGT), glucose, lipase, pH and decreased values in albumin, fibrinogen, high-density lipoprotein (HDL), hemoglobin, low-density lipoprotein cholesterol (LDL-D), and total proteins from their blood tests. In addition, APIP patients have decreased numbers in red cells but increased numbers in white blood cells and increased ratio of neutrophil/lymphocyte (N/L). Among these factors, N/LR, GGT, lipase, and HDL are significantly associated with APIP. This study suggests that the combination of those factors serve as a panel of indicators for early-onset prognosis of APIP.GGT, lipase, HDL, and N/LR can serve as a panel of factors to predict APIP. More case studies are important to further evaluate the predicting power of this panel factors in APIP.

Associations between hematopoietic growth factors and risks of venous thromboembolism, stroke, ischemic heart disease and myelodysplastic syndrome: findings from a large population-based cohort of women with breast cancer

PURPOSE

To determine the risk of venous thromboembolism (VTE), stroke, ischemic heart disease, and myelodysplastic syndrome (MDS) in association with the receipt of colony-stimulating factors (CSFs) and/or erythropoiesis-stimulating agents (ESAs) in women with breast cancer.

METHODS

We studied 77,233 women with breast cancer aged ≥65 in 1992-2009 from the Surveillance, Epidemiology, and End Results-Medicare linked data with up to 19 years of follow-up.

RESULTS

Incidence of VTE increased from 9 cases in women receiving no chemotherapy and no CSFs/ESAs to 22.79 cases per 1,000 person-years in those receiving chemotherapy with CSFs and ESAs. Women with chemotherapy who received both CSFs and ESAs (adjusted hazard ratio and 95 % confidence interval 2.01, 1.80-2.25) or received ESAs without CSFs (2.03, 1.74-2.36) were twice as likely to develop VTE than those receiving no chemotherapy and no CSFs/ESAs, whereas those receiving CSF alone without ESA were 64 % more likely to have VTE (1.64, 1.45-1.85). Risk of MDS was significantly increased by fivefold in patients receiving ESA following chemotherapy.

CONCLUSIONS

Receipts of CSFs and ESAs were significantly associated with an increased risk of VTE in women with breast cancer. Use of ESAs was significantly associated with substantially increased risks of MDS. These findings support those of previous studies.

Risks of Venous Thromboembolism, Stroke, Heart Disease, and Myelodysplastic Syndrome Associated With Hematopoietic Growth Factors in a Large Population-Based Cohort of Patients With Colorectal Cancer

PURPOSE

To determine the relationship between the receipt of colony-stimulating factors (CSFs) with erythropoiesis-stimulating agents (ESAs) and the risk of developing venous thromboembolism (VTE), stroke, heart disease, and myelodysplastic syndrome (MDS) in patients with colorectal cancer.

METHODS

We studied 80,925 patients diagnosed with colorectal cancer at age ≥ 65 years in 1992-2009 from the nationwide 16 areas of the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data. Cumulative incidence and the time to events Cox hazard regressions were used to explore the risks of outcomes in association with the receipt of CSFs and ESAs.

RESULTS

Patients who received chemotherapy (CT) with both CSF and ESA were 58% more likely to develop VTE than those who received CT without CSF and ESA (hazard ratio, 1.58; 95% confidence interval, 1.43-1.76). The risk of stroke appeared to be not associated with the use of CSF and ESA, whereas the risk of heart disease was only significantly elevated in those patients who did not receive CT but received ESA. The risk of acute myeloid leukemia or MDS was significantly increased 4- to 9-fold in patients who received ESA, regardless of receipt of CT or CSF.

CONCLUSION

The use of ESAs was significantly associated with a substantially increased risk of MDS in patients with colorectal cancer. The use of CSFs and ESAs was also significantly associated with a moderately increased risk of VTE and a slightly elevated risk of heart disease.

Accelerated death rate in population-based cohort of persons with traumatic brain injury

OBJECTIVES

To determine the influence of preexisting heart, liver, kidney, cancer, stroke, and mental health problems and examine the influence of low socioeconomic status on mortality after discharge from acute care facilities for individuals with traumatic brain injury.

PARTICIPANTS

Population-based retrospective cohort study of 33695 persons discharged from acute care hospital with traumatic brain injury in South Carolina, 1999-2010.

MAIN MEASURES

Days elapsing from the dates of injury to death established the survival time (T). Data were censored at the 145th month. Multivariable Cox regression was used to examine the independent effect of the variables on death. Age-adjusted cumulative probability of death for each chronic disease of interest was plotted.

RESULTS

By the 70th month of follow-up, rate of death was accelerated from 10-fold for heart diseases to 2.5-fold for mental health problems. Adjusted hazard ratios for diseases of the heart (2.13), liver-renal (3.25), cancer (2.64), neurological diseases and stroke (2.07), diabetes (1.89), hypertension (1.43), and mental health problems (1.59) were highly significant (each with P < .001). Compared with persons with private insurance, the hazard ratio was significantly elevated with Medicaid (1.67), Medicare (1.54), and uninsured (1.27) (each with P < .001).

CONCLUSION

Specific chronic diseases strongly influenced postdischarge mortality after traumatic brain injury. Low socioeconomic status as measured by the type of insurance elevated the risk of death.

Association between chemotherapy and cognitive impairments in a large cohort of patients with colorectal cancer

No population-based study has been conducted on the relationship between chemotherapy and the risk of cognitive impairments in patients with colorectal cancer. This study aimed to determine this association in a large population-based cohort of patients. We studied 72,374 men and women who were diagnosed with stages I-III colorectal cancer at age ≥ 65 years from 1991 through 2002 from 16 regions in the Surveillance, Epidemiology and End Results program who were free of cognitive impairments at baseline with up to 17 years of follow-up and also studied 15,921 matched cohorts based on the propensity of receiving chemotherapy. The cumulative incidence of drug-induced dementia at 5 years was 16.2 cases per 1,000 persons for the chemotherapy group and 12.4 cases per 1,000 persons for the no chemotherapy group. Overall, patients who received chemotherapy were 24% significantly more likely to develop drug-induced dementia compared to those without chemotherapy after adjusting for patient and tumor characteristics (hazard ratio 1.24, 95% confidence interval 1.05-1.47). The significantly increased risk was only observed in those without mood disorder who received chemotherapy in the entire cohort (1.26, 1.06-1.50) and in the matched cohort (1.29, 1.04-1.59). The risk of developing Alzheimer's disease, vascular dementia or other dementias was significantly lower in patients receiving chemotherapy compared to those without chemotherapy regardless of mood disorder status. In conclusion, there was a significant association between chemotherapy and the risk of developing drug-induced dementia in patients with colorectal cancer without mood disorder, but chemotherapy was associated with a decreased risk of other dementias.

Abusive head trauma in young children: a population-based study

OBJECTIVE

The objectives of this study were to provide population-based incidence estimate of abusive head trauma (AHT) in children aged 0 to 5 years from inpatient and emergency department (ED) and identify risk characteristics for recognizing high-risk children to improve public health surveillance.

METHODS

This was a retrospective cohort study based on children's first encounter in ED or hospital admission with a diagnosis of head trauma (HT), 2000-2010. The relationship between clinical markers and AHT was examined controlling for covariables in the model using Cox hazards regression. Kaplan-Meier incidence probability was plotted, and the number of weeks elapsing from date of birth to the first encounter with HT established the survival time (T).

RESULTS

Twenty-six thousand six hundred eighty-one children had HT, 502 (1.8%) resulted from abuse; 42.4% was captured from ED. Incidence varied from 28.9 (95% confidence interval [CI], 27.9-37.4) in infants to 4.1 (95% CI, 2.4-5.7) in 5-year-olds per 100,000 per year. Adjusted hazard ratio was 20.3 (95% CI, 10.9-38.0) for intracranial bleeding and 11.4 (95% CI, 8.57-15.21) for retinal hemorrhage.

CONCLUSIONS

Incidence estimates of AHT are incomplete without including ED. Intracranial bleeding is a cardinal feature of AHT to be considered in case ascertainment to improve public health surveillance.

High concentrations of AGE-LDL and oxidized LDL in circulating immune complexes are associated with progression of retinopathy in type 1 diabetes

OBJECTIVE

To determine whether immunocomplexes (ICs) containing advanced glycation end product (AGE)-LDL (AGE-LDL) and oxidized LDL (oxLDL) contribute to the development of retinopathy over a 16-year period in subjects with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Levels of AGE-LDL and oxLDL in ICs were measured in 517 patients of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) cohort. Retinopathy was assessed by stereoscopic fundus photography. Cox proportional hazards models were used to assess the effect of AGE-LDL-ICs and oxLDL-ICs on retinopathy progression.

RESULTS

In unadjusted models, higher baseline levels of AGE-LDL-ICs and oxLDL-ICs significantly predicted progression of diabetic retinopathy outcomes. After adjustment by study-design variables (treatment group, retinopathy cohort, duration of type 1 diabetes, and baseline albumin excretion rate [AER], hemoglobin A(1c) (HbA(1c)), and Early Treatment Diabetic Retinopathy Study [ETDRS] score), one SD increase in IC levels was associated with 47% (hazard ratio [HR] 1.47 [95% CI 1.19-1.81]; AGE-LDL-IC) and 45% (1.45 [1.17-1.80]; oxLDL-IC) increased risk of developing proliferative diabetic retinopathy (PDR) and 37% (1.37 [1.12-1.66]; to both ICs) increased risk of progressing to severe nonproliferative retinopathy. Analyses were stratified by retinopathy cohort because results differed between primary and secondary cohorts. For AGE-LDL-ICs, HR for progression to PDR was 2.38 (95% CI 1.30-4.34) in the primary cohort and attenuated in the secondary cohort (1.29 [1.03-1.62]). Similar results were observed for oxLDL-ICs.

CONCLUSIONS

Increased levels of AGE-LDL and oxLDL in ICs are associated with increased risk for progression to advanced retinopathy in patients with type 1 diabetes, indicating that the antibody response to modified LDL plays a significant role in retinopathy progression.

Longitudinal incidence of adverse outcomes of age-related macular degeneration

OBJECTIVE

To describe the visual, functional, and general health complication rates associated with age-related macular degeneration (AMD) in a nationally representative longitudinal sample of elderly persons.

METHODS

This is a longitudinal retrospective cohort study (January 1, 1994-December 31, 2004) that used Medicare claims data. We identified beneficiaries aged 68 years and older who had newly diagnosed AMD in 1994 (n = 32,702) and age-, sex-, and race-matched controls who had routine eye surveillance and no diagnosis of AMD throughout the observational period (n = 32,702). Main outcome measures included cumulative incidence of vision loss, blindness, hip fracture, depression, and nursing home placement and prevalence of 16 general health conditions.

RESULTS

Elderly individuals with newly diagnosed AMD had higher rates of blindness, vision loss, depression, hip fracture, and residence in a nursing home than those without AMD during a 10-year follow-up period. Individuals with AMD also had a higher prevalence of 11 of 16 general health conditions compared with controls.

CONCLUSIONS

Individuals aged 68 years and older with AMD had higher rates of visual and functional impairments and had more illness than controls. Our findings demonstrate the substantial resource commitment of caring for the multifaceted health issues of persons diagnosed with AMD.

Longitudinal rates of postoperative adverse outcomes after glaucoma surgery among medicare beneficiaries 1994 to 2005

PURPOSE

To determine longitudinal rates of postoperative adverse outcomes after incisional glaucoma surgery in a nationally representative longitudinal sample.

DESIGN

Retrospective, longitudinal cohort analysis.

PARTICIPANTS

Medicare beneficiaries >or=68 years who underwent a primary trabeculectomy (PT), trabeculectomy with scarring (TS), or glaucoma drainage device (GDD) implantation from 1994 to 2003 with follow-up through 2005.

INTERVENTION

Primary trabeculectomy, TS, and GDD were identified from International Classification of Diseases (ICD-9-CM) and Current Procedural Terminology (CPT) procedure codes. Change in rates of postoperative adverse outcomes associated with these 3 surgical interventions was analyzed by cumulative incidence rates and Cox proportional hazards model regression; regression analysis controlled for prior adverse outcome measures (3-year run-up) and demographic variables.

MAIN OUTCOME MEASURES

First-, second-, and sixth-year cumulative rates and probability of experiencing serious adverse outcomes (retinal detachment, endophthalmitis, suprachoroidal hemorrhage), less serious adverse outcomes (choroidal detachment, corneal edema, hypotony), and receipt of additional glaucoma surgery were identified through Medicare claims for each treatment group.

RESULTS

At the 1-year follow-up, rates of severe adverse outcomes were higher among beneficiaries in the GDD group (2.0%) relative to the PT (0.6%) and TS groups (1.3%). Controlling for prior adverse outcomes to the surgery and demographic factors in Cox proportional analysis, differences were often reduced, but generally remained statistically and clinically significant. Rates of severe outcomes, less severe outcomes, corneal edema, and low vision/blindness were higher for persons undergoing GDD than PT or TS. However, rates of reoperation were higher for TS than GDD.

CONCLUSIONS

The risk for adverse outcomes was higher in GDD than in PT surgery or TS, controlling for a number of important case mix and demographic factors.