The hazards of using active clinic patients as a source of subjects for clinical studies

Natural history of anal dysplasia in an HIV-infected clinical care cohort: estimates using multi-state Markov modeling

OBJECTIVES

(1) To model the natural history of anal neoplasia in HIV-infected patients using a 3-state Markov model of anal cancer pathogenesis, adjusting for cytology misclassification; and (2) to estimate the effects of selected time-varying covariates on transition probabilities.

DESIGN

A retrospective cytology-based inception screening cohort of HIV-infected adults was analyzed using a 3-state Markov model of clinical pathogenesis of anal neoplasia.

METHODS

Longitudinally ascertained cytology categories were adjusted for misclassification using estimates of cytology accuracy derived from the study cohort. Time-varying covariate effects were estimated as hazard ratios.

RESULTS

(1) There was a moderate to high probability of regression of the high grade squamous intraepithelial lesion (HSIL) state (27-62%) at 2 years after initial cytology screening; (2) the probability of developing invasive anal cancer (IAC) during the first 2 years after a baseline HSIL cytology is low (1.9-2.8%); (3) infrared coagulation (IRC) ablation of HSIL lesions is associated with a 2.2-4.2 fold increased probability of regression to <HSIL; and (4) antiretroviral therapy, suppressed HIV plasma viral load, and CD4 ≥350/mm3 are each associated with reduced probability of progression from <HSIL to HSIL.

CONCLUSIONS

The finding of moderate to high rates of regression of the HSIL state accompanied by low rates of progression to IAC should inform both screening and precursor treatment guideline development. There appears to be a consistent and robust beneficial effect of antiretroviral therapy, suppressed viral load, and higher CD4 on the transition from the <HSIL state to the HSIL state.

Are We Selecting the Right Patients for Stroke Rehabilitation in Nursing Homes?

OBJECTIVE

To examine the effect of stroke rehabilitation in the nursing home on community discharge rates and functional status among patients stratified by propensity to receive rehabilitation.

DESIGN

Retrospective cohort.

SETTING

Medicaid-certified nursing homes (N=945) in Ohio.

PARTICIPANTS

Patients with stroke (N=2013) admitted to an Ohio nursing home.

INTERVENTION

Rehabilitation therapy services.

MAIN OUTCOME MEASURES

The propensity to receive rehabilitation, used to adjust for selection bias, was calculated for each patient by using a logistic regression model. Community discharge and change in functional status, measured by using a crosswalk to the FIM instrument, were determined 3 months after admission.

RESULTS

By 3 months after admission, 36.9% of the patients were discharged to the community, 16.6% had died, and 46.5% remained in the nursing home. The overall effect of rehabilitation on community discharge (relative risk [RR]=1.58; 95% confidence interval [CI], 1.33-1.85) was not homogeneous across subgroups stratified by propensity to receive rehabilitation. Patients less likely to receive rehabilitation, as measured by a lower propensity score, had a significant benefit in terms of community discharge (RR=1.65; 95% CI, 1.35-1.97), but those more likely to receive services did not (RR=1.21; 95% CI, 0.87-1.56). Among long-term nursing home residents, rehabilitation services were not associated with improved functional status.

CONCLUSIONS

With respect to community discharge, patients who were less likely to receive rehabilitation therapy appear to receive greater benefit from rehabilitation services than those who were more likely to receive rehabilitation. This finding raises concerns about current selection practices for rehabilitation services. Research is needed to identify the patients most likely to benefit, especially in the present fiscally constrained reimbursement environment.

Gastroesophageal reflux disease related to diabetes: Analysis of 241 cases with type 2 diabetes mellitus

BACKGROUND AND AIM

We examined the incidence of symptomatic gastroesophageal reflux disease (GERD) in patients with type 2 diabetes mellitus (DM).

METHODS

Patients comprised those with DM or chronic hepatitis C (CHC) who visited Osaka Prefectural General Hospital in the same study period. Reflux symptoms were examined using a self-administered questionnaire. A total score of 4 or more was considered an indication of symptomatic GERD. Disease duration, hemoglobinA1c and diabetic complications were assessed.

RESULTS

Patients with DM (n=241) or CHC (n=42) were recruited for the study. Of the 241 patients with DM, 100 (41.5%) reported experiencing upper gastrointestinal symptoms, whereas only 9 of 42 (21.4%) patients with CHC reported upper gastrointestinal symptoms (P=0.0137). Sixty-one patients (25.3%) with DM had reflux symptoms but only four patients (9.5%) with CHC reported reflux symptoms. The incidence of symptomatic GERD was significantly higher in patients with DM than in those with CHC (P=0.0219). Patients with DM for less than 5 years had a 2.4-fold higher incidence of GERD than patients with CHC. The incidence tended to rise with increased disease duration. Patients with diabetic complications reported reflux symptoms more frequently. The incidence decreased, however, in DM patients who had these conditions for more than 16 years.

CONCLUSIONS

Type 2 diabetes mellitus is a risk factor for symptomatic GERD. In DM patients, use of oral hypoglycemic agents, body mass index, disease duration and the quality of diabetic control influenced the incidence of GERD.

Mortality experience of Navajos with type 2 diabetes mellitus

OBJECTIVES

We sought to determine the contribution of type 2 diabetes mellitus to mortality in a Navajo population, and to assess the impact of pre-existing coronary heart disease on this relationship.

METHODS

A cohort of 77 Navajos with type 2 diabetes mellitus and 77 non-diabetic controls matched on age, gender and community of residence were followed for an 18-year period, from 1974 to 1992.

RESULTS

The vital status of 152 of the 154 study subjects was ascertained at 18-year follow-up. There were 30 deaths (39%) in the type 2 diabetes group and 13 (17%) in the control group during the 18-year period which was significantly different in bivariate matched pairs analysis (risk ratio = 3.12, McNemar's chi 2 = 7.76, p < 0.01). Multivariate conditional logistic response models (risk ratio = 3.02, 95% CI 1.21, 7.53) and stratification analysis (McNemar's Summary chi 2 = 8.05, 2 df, p < 0.05), confirmed that survival was significantly different for the two groups, even when controlling for baseline cardiovascular comorbidity and hypertension.

CONCLUSION

These data describe the mortality impact of the epidemic of type 2 diabetes and cardiovascular disease now accelerating among the Navajo. The significant mortality differences between the diabetes and non-diabetes groups and the continuing rise in prevalence of type 2 diabetes underscore the need for an effective community-based approach to diabetes prevention among the Navajo.

Comparative cost-effectiveness analysis of theophylline and ipratropium bromide in chronic obstructive pulmonary disease. A three-center study

The charts of 311 patients receiving theophylline (T) and 289 patients receiving ipratropium bromide (IB) for COPD were reviewed to determine the total costs and cost-effectiveness of these 2 agents in 3 different health-care settings. A direct cost-accounting method assessed cost, and a Markov decision-analysis model calculated cost-effectiveness. Costs to treat toxic effects were greater for T versus IB. The types and incidences of toxic effects, by drug, were similar among the three centers. Overall costs for T were $121.40 per patient per therapy-month versus $84.56 per patient per therapy-month for IB, as determined by the cost-accounting method. The marginal cost was $366 for T over IB when extrapolated over 1 year using the Markov model. The Markov model also predicted that patients receiving IB had a greater number of complication-free therapy-months (measurement of effectiveness) than patients receiving T. We conclude that treatment with IB was less costly and more cost-effective than T.

Risk factors for pressure sores. A comparison of cross-sectional and cohort-derived data

The purpose of this study was to identify prospectively risk factors for pressure sores and to compare these results with a cross-sectional analysis in the same population. Medical records on all admissions to a chronic care hospital over a 13-month period were reviewed. Data on potential risk factors were abstracted from the initial history, physical examination, nursing assessment, and laboratory studies. Pressure sore status on admission and at three weeks was determined from a standardized from completed on all patients with a score. The cross-sectional analysis was performed by comparing patients with and without a pressure sore at the time of admission. The cohort analysis used patients initially without a pressure sore and monitored for a new sore at three weeks. Factors associated with pressure sores on univariate testing were entered into a stepwise logistic regression model. One hundred of the 301 admissions presented with a pressure sore. Factors significantly associated with the presence of a sore were altered level of consciousness (OR = 4.1), bed- or chair-bound (OR = 2.4), impaired nutritional intake (OR = 1.9), and hypoalbuminemia (OR = 1.8 for 10 mg/mL decrease). Of the 185 patients without a pressure sore, 20 (10.8%) developed a sore. Factors significantly associated with the development of a new pressure sore were a history of cerebrovascular accident (OR = 5.0), bed- or chair-bound (OR = 3.8), and impaired nutritional intake (OR = 2.8). Neither urinary nor fecal incontinence, nor the presence of hypoalbuminemia, was associated with sore development. We have prospectively identified risk factors for pressure sores.(ABSTRACT TRUNCATED AT 250 WORDS)

The clinical prognosis of HIV-1 infection: a review of 32 follow-up studies

Thirty-two follow-up studies of patients with HIV-1 infection, but without AIDS at baseline, were examined for information on the risk of developing AIDS or other conditions. Disease progression in asymptomatic groups was similar to that found in patients with persistent generalized lymphadenopathy (PGL) without other symptoms. Among these asymptomatic and PGL groups, the risk of developing AIDS reached 10% to 15% between 24 and 36 months of follow up. The risk of progression to AIDS continued to increase in the studies with longer follow-up periods, reaching 36% at 88 months. However, more than 40% of "high-risk" groups (characterized by the presence of constitutional symptoms, oral thrush, herpes zoster, and/or low T4 counts) developed AIDS after only 36 months of follow-up. Reliable information about progression to other states (e.g., AIDS-related complex) has not been consistently provided.