Effect of low-molecular-weight heparin on potassium homeostasis.

BACKGROUND: Low-molecular-weight heparins (LMWHs) are being preferred to unfractionated heparin (UFH) because of their superior convenience and a comparable or slightly better toxicity profile. Whether LMWH has an inhibitory effect on aldosterone that causes hyperkalemia is yet uncertain. METHODS: Twenty-eight patients (all male; mean age: 70 years, range 52-87 years) placed on LMWH therapy (40 mg subcutaneously every 12 h) for deep venous thrombosis prophylaxis after an operation were included in the study. Transtubular potassium concentration gradient (TTKG) was calculated 1 day prior to LMWH therapy and again after 4 days of treatment. Of the 28 patients enrolled in the study, we were able to calculate the TTKG in only 19 patients: 9 had a urinary osmolarity (either before or after LMWH therapy) less than the serum osmolarity, making the TTKG calculation unreliable. The Wilcoxon signed-rank test was used to analyze differences in the median serum potassium levels and TTKG before and after LMWH therapy. RESULTS: All patients had adequate renal function (creatinine clearance >90 ml/min). Mean (+/- SD) serum potassium concentration before LMWH was 4.25 (+/- 0.40) mmol/dl. It increased to 4.35 (+/- 0.41) mmol/dl after initiating LMWH therapy (p = 0.09). Similarly, the mean (+/- SD) TKKG calculated was 5.52 (+/- 2.33) before and 5.97 (+/- 3.06) after 4 days of LMWH (p = 0.54). CONCLUSIONS: Unlike UFH, LMWH (Lovenox in doses used for postoperative prophylaxis against deep venous thrombosis does not seem to have a significant effect on potassium homeostasis.

An epidemiological study evaluating the relationship of distance from a tertiary care cancer center to early detection of colorectal carcinoma.

OBJECTIVE: AJCC stage at diagnosis determines the treatment approach and indirectly predicts outcome in patients with colorectal carcinoma. The purpose of our study was to investigate whether there was a delay in diagnosis leading to a more advanced stage at diagnosis (which affects outcome) of patients with colorectal cancers because of distance from a referral center, after positive fecal occult blood testing (FOBT). DESIGN: Our retrospective observational study involved all cases of colonic and rectosigmoid cancers that were referred for an endoscopic procedure after an initial positive FOBT done as a part of routine screening in asymptomatic patients. PARTICIPANTS: Roger Maris Cancer Center and University of North Dakota School of Medicine and Health Sciences. RESULTS: Between the years 1996-2001, 178 subjects with biopsy-proven colon cancer and 80 patients with rectosigmoid cancer were included in our study. Pearson's correlation coefficients were constructed to look at the relationship between distance from a referral center (place where the diagnosis was made) and stage at diagnosis in patients with colonic and rectosigmoid malignancies. For the colon cancer group, the regression coefficient between AJCC stage at diagnosis and distance from the referral center was 0.013 and for rectosigmoid cancers it was 0.12. Even after stratifying distances into tertiles, the correlation coefficients did not show a significant relationship (0.04 for colon and 0.16 for rectosigmoid cancers). CONCLUSION: Distance (of residence) from a tertiary care center does not seem to be a barrier to early diagnosis of colorectal carcinoma and primary care providers in rural settings are referring patients appropriately leading to optimal outcomes.

Predictive value of clinical features at initial presentation in pancreatic adenocarcinoma: a series of 308 cases.

Pancreatic cancer is the fourth leading cause of cancer death in both men and women with a mortality incidence ratio of 0.99. In an effort to describe the role of clinical features at initial presentation, we conducted a retrospective observational study in patients with a biopsy-proven diagnosis of adenocarcinoma of the pancreas. Between 1986 and 2001, 308 patients (160 males, 148 females) were diagnosed with pancreatic adenocarcinoma. The mean age at diagnosis was 70.1 yr (range: 34-96 yr). The mean survival was 7.6 mo (range: 0-97 mo). Statistical analysis was performed using log-rank tests and analysis of variance. As expected, age at diagnosis was a significant factor affecting survival, with older patients doing relatively poorly (p < 0.05). Patients with a good performance status performed significantly better than those with a poor performance status (p < 0.01). In addition, the presence of the tumor in the head of the pancreas was a predictor for improved survival (p < 0.01). Although smoking increased the chances of detection at an earlier age, neither diabetes mellitus nor a positive smoking history had a statistically significant effect on the survival. Pancreatic adenocarcinoma is a disease of the elderly associated with a poorer outcome. Knowledge of possible clinical predictors of survival may lead to better patient counseling regarding prognosis.