Biomedical subjects

Michael D deB Edwardes

Publications and source records attributed to Michael D deB Edwardes.

4 recordsLinked to original sources

PubMed2003

Parathyroid hormone-related peptide and survival of patients with cancer and hypercalcemia.

PURPOSE: Parathyroid hormone-related peptide (PTHrP) is the predominant cause of malignancy-associated hypercalcemia. However, its prognostic utility is unclear. We aimed to determine the prognostic value of serum PTHrP levels in patients who had hypercalcemia associated with malignancy. METHODS: In this prospective case series, we evaluated 76 patients with a diagnosis of cancer and hypercalcemia (serum calcium level >/=10.3 mg/dL on at least two occasions). PTHrP levels >/=1 pmol/L were considered elevated. We used multivariate Cox regression analysis to identify factors associated with mortality. RESULTS: Fifty patients (66%) died during follow-up. In a multivariate analysis, higher pretreatment calcium levels and elevated PTHrP levels were associated with increased mortality, with effects of PTHrP varying by age (P = 0.03). Survival was associated with pretreatment calcium levels both in patients over 65 years of age (hazard ratio [HR] per mg/dL = 1.5; 95% confidence interval [CI]: 1.2 to 1.8; P <0.001) and in patients aged 65 years or less (HR = 1.3; 95% CI: 1.1 to 1.5; P = 0.003). Adjusted for pretreatment calcium levels, elevated PTHrP levels were associated with increased mortality in patients aged </=65 years (HR = 3.8; 95% CI: 1.6 to 8.8; P = 0.002), but not in older patients (HR = 0.7; 95% CI: 0.3 to 1.9; P = 0.51). CONCLUSION: PTHrP is a useful prognostic factor in malignancy-associated hypercalcemia, at least in patients aged </=65 years.

Biomarkers↗

PubMed2003

Statistical analysis of correlated data using generalized estimating equations: an orientation.

The method of generalized estimating equations (GEE) is often used to analyze longitudinal and other correlated response data, particularly if responses are binary. However, few descriptions of the method are accessible to epidemiologists. In this paper, the authors use small worked examples and one real data set, involving both binary and quantitative response data, to help end-users appreciate the essence of the method. The examples are simple enough to see the behind-the-scenes calculations and the essential role of weighted observations, and they allow nonstatisticians to imagine the calculations involved when the GEE method is applied to more complex multivariate data.

Body Height↗

PubMed2003

Psychosocial determinants of relapse in ulcerative colitis: a longitudinal study.

OBJECTIVES: To determine the association between psychosocial characteristics and time to relapse in patients with inactive ulcerative colitis. METHODS: Sixty patients with clinically and endoscopically inactive ulcerative colitis were followed for 1 yr, or less if they relapsed. Demographic, psychosocial, and clinical data were obtained. Stressful life events (Psychiatric Epidemiology Research Interview Life Events Scale), psychological distress (Symptom Checklist-90R), and perceived stress (Perceived Stress Scale) were recorded monthly by self-report. Multivariate time-dependent Cox regression was used to identify the independent determinants of earlier time to clinical relapse. RESULTS: The patients' mean age was 39 yr (SD = 9.4), 37 (62%) were female, and 22 (37%) relapsed during the 1-yr follow-up. Univariate Cox regression indicated a weak association between number of stressful events in the preceding month and time to relapse (p = 0.09). This association strengthened in multivariate analysis (p = 0.02, hazard ratio = 1.26 per event, 95% CI = 1.04-1.53) after adjustment for significant covariates. CONCLUSIONS: After controlling for demographic and clinical variables, more recent stressful events were associated with earlier time to relapse. These findings, which support a biopsychosocial model of disease, might help clinicians identify patients who might benefit from more intensive maintenance medical therapy and behavioral medicine interventions to reduce stress and improve coping.

Adult↗

PubMed2002

Malignancy after renal transplantation: incidence and role of type of immunosuppression.

BACKGROUND: Cancer, particularly skin cancer and lymphoma, is a complication of posttransplantation immunosuppression. We investigated the characteristics of cancers in our renal transplant population, the role of type of immunosuppression on cancer incidence, and whether newer, more potent immunosuppressive agents produce cancers sooner after transplantation. METHODS: The charts of patients who developed cancer after renal transplantation between 1958 and 2000 were reviewed. Statistical analyses were performed with the mid-P version of Fisher's exact test for 2 x 2 tables for incidence comparison of cancer and with Student's t-test for differences between mean times to cancer. RESULTS: Between 1958 and 2000, 924 transplantations in 760 patients were performed. We found a cancer incidence of 12.2%. The most frequent cancers were skin and genitourinary. The overall mortality was 54%. We found an increased incidence of cancer in the group of patients in the cyclosporine era and for patients >or=45 years at transplantation. Cancer did not develop sooner in the cyclosporine group. CONCLUSIONS: The distribution of types of cancer was similar to that reported in the literature. The mortality rate was high. The incidence of cancer was higher in the cyclosporine era in patients >or=45 years at transplantation.

Adolescent↗