Douglas D. Bradham

The Use and Interpretation of Quasi-Experimental Studies in Infectious Diseases

Quasi-experimental study designs, sometimes called nonrandomized, pre-post-intervention study designs, are ubiquitous in the infectious diseases literature, particularly in the area of interventions aimed at decreasing the spread of antibiotic-resistant bacteria. Little has been written about the benefits and limitations of the quasi-experimental approach. This article outlines a hierarchy of quasi-experimental study design that is applicable to infectious diseases studies and that, if applied, may lead to sounder research and more-convincing causal links between infectious diseases interventions and outcomes.

Exercise rehabilitation improves functional outcomes and peripheral circulation in patients with intermittent claudication: a randomized controlled trial.

OBJECTIVE: To determine the effects of a 6‐month exercise program on ambulatory function, free‐living daily physical activity, peripheral circulation, and health‐related quality of life (QOL) in disabled older patients with intermittent claudication.

Risk Factors for Imipenem-Resistant Pseudomonas aeruginosa among Hospitalized Patients

Risk factors for the nosocomial recovery of imipenem-resistant Pseudomonas aeruginosa (IRPA) were determined. A case-control study design was used for the comparison of 2 groups of case patients with control patients. The first group of case patients had nosocomial isolation of IRPA, and the second group had imipenem-susceptible P. aeruginosa (ISPA). Control patients were selected from the same medical or surgical services from which case patients were receiving care when isolation of IRPA occurred. Risk factors analyzed included antimicrobials used, comorbid conditions, and demographic variables. IRPA was recovered from 120 patients, and ISPA from 662 patients. Imipenem (odds ratio [OR], 4.96), piperacillin-tazobactam (OR, 2.39), vancomycin (OR, 1.80), and aminoglycosides (OR, 2.19) were associated with isolation of IRPA. Vancomycin (OR, 1.64), ampicillin-sulbactam (OR, 2.00), and second-generation cephalosporins (OR, 2.00) were associated with isolation of ISPA. Antibiotics associated with ISPA are different from antibiotics associated with IRPA. The OR for imipenem as a risk factor for IRPA is less than that reported from studies in which control group selection was suboptimal.

The economic impact of psoriasis increases with psoriasis severity

BACKGROUND Psoriasis treatments are known to be costly, but little is known about the financial impact of psoriasis and the way in which it relates to the severity of the disease. OBJECTIVE This study was performed to obtain an estimate of the treatment costs faced by patients with psoriasis. METHODS A total of 578 anonymous mail surveys were distributed to patients with psoriasis; 318 surveys were returned (55%). Psoriasis severity was assessed with the previously validated Self-Administered Psoriasis Area Severity Index (SAPASI). RESULTS The total and out-of-pocket expenses to care for psoriasis were correlated with psoriasis severity (r = 0.26, p = 0.0001). There were no sex (p = 0.9) or racial (p = 0.4) differences in total expenditures. Severity was correlated with how bothersome to the patient was the cost of treatment (r = 0.30, p = 0.0001), the time required for treatment (r = 0.38, p = 0.0001), and the time lost from work (r = 0.23, p = 0.0001). Lower quality of life at work and in money matters also correlated with severity of psoriasis. Higher family income was associated with less time spent caring for psoriasis and less interference with work around the home. CONCLUSION As expected, the expenses caring for psoriasis are greater for patients with more severe disease. These costs and other financial implications are associated with lower quality of life for patients with more severe psoriasis.

Rehospitalization After Hip Fracture: Predictors and Prognosis from a National Veterans Study

OBJECTIVES: To estimate the risk and long‐term prognostic significance of 30‐day readmission postdischarge of a 4‐year cohort of elderly veterans first admitted to Medicare hospitals for treatment of hip fractures (HFx), controlling for comorbidities.

Cost-effectiveness of aerobic and resistance exercise in seniors with knee osteoarthritis

PURPOSE The purpose of this study was to determine, in a randomized clinical trial of 439 individuals with knee osteoarthritis, the incremental cost-effectiveness of aerobic versus weight resistance training, compared with an education control intervention. METHODS Cost estimates of the intervention were based upon the cost of purchasing from the community similar services to provide exercise or health education. Effect at 18 months was measured using several variables, including: self-reported disability score, 6-min walking distance, stair climb, lifting and carrying task, car task, and measures of pain frequency and pain intensity on ambulation and transfer. RESULTS The total cost of the educational intervention was

Time of Birth, Residential Solar Radiation and Age at Onset of Multiple Sclerosis

343.98 per participant. The aerobic exercise intervention cost

Sun Exposure, Vitamin D and Age at Disease Onset in Relapsing Multiple Sclerosis

323.55 per participant, and the resistance training intervention cost

Improving efficiency in active surveillance for methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus at hospital admission.

325.20 per participant. On all but two of the outcome variables, the incremental savings per incremental effect for the resistance exercise group was greater than for the aerobic exercise group. CONCLUSION The data obtained from this study suggest that, compared with an education control, resistance training for seniors with knee osteoarthritis is more economically efficient than aerobic exercise in improving physical function. However, the magnitude of the difference in efficiency between the two approaches is small.

A National Perspective of Medicare Expenditures for Elderly Veterans with Hip Fractures

Backgrounds/Aim: Gestational and early life events have been suggested to contribute to multiple sclerosis (MS) susceptibility. We assessed the effects of time and place of birth on the age at onset of MS symptoms. Methods: We selected a national cohort of 967 veterans from the Multiple Sclerosis Surveillance Registry for whom month and season (time) of birth, and birthplace (city and state) were available. Multiple linear regression analyses were used to examine the association between time of birth, birthplace latitude and solar radiation, and the age at onset of MS symptoms among the study sample. Results: Patients with a relapsing form of the disease (R-MS), who were born in winter and whose birthplace was in low solar radiation areas, had disease symptom onset on average 2.8 years earlier than those born in seasons other than winter and in medium- and high-solar radiation areas (p = 0.02). Conclusions: These results suggest that exposure early in life to geographical and seasonal factors, possibly related to the protective effect of sunlight, and thus vitamin D, is associated with a delay in MS symptom onset. Other larger studies are required to examine the period-specific (from conception to adulthood) environmental factors that are associated with MS susceptibility.