Altered mental status and low anion gap in a patient with sickle cell anemia: a case report.

INTRODUCTION: It is challenging to diagnose two coexisting medical conditions if the symptoms are overlapping. This is further confounded if the patient presents with an unexplained deterioration in mental status. A low anion gap or a zero anion gap is an uncommon clinical finding and has few differential diagnoses. This test therefore has important implications in correctly identifying underlying medical conditions. CASE PRESENTATION: A 50-year-old African American male patient with sickle cell disease presented with refractory anemia, recurrent bone pains and encephalopathy. Routine testing failed to explain his mental deterioration. A laboratory finding of a low anion gap pointed in the direction of multiple myeloma as the underlying cause. This in turn led to an appropriate and timely course of treatment and clinical improvement. CONCLUSION: We present a very rare case of sickle cell anemia with coexisting multiple myeloma. This case sparks an interesting discussion on the anion gap, of which a clinician should be aware. It highlights the importance of the use of a verifiable anion gap in diagnosing medical conditions beyond the routine diagnosis of acid base disorders.

Do pediatricians manage influenza differently than internists?

BACKGROUND: Little is known about how pediatricians or internists manage influenza symptoms. Recent guidelines on antiviral prescribing by the Centers for Disease Control and Prevention (CDC) make almost no distinction between adults and children. Our objective was to describe how pediatricians in two large academic medical institutions manage influenza and compare them to internists. METHODS: At the end of the 2003-4 influenza season, we conducted a cross sectional on-line survey of physician knowledge, attitudes and practices regarding rapid diagnostic testing and use of antiviral therapy for influenza at two large academic medical centers, one in Massachusetts and the other in Texas. We collected data on self-reported demographics, test use, prescribing practices, and beliefs about influenza and anti-influenza drugs. RESULTS: A total of 107 pediatricians and 103 internists completed the survey (response rate of 53%). Compared to internists, pediatricians were more likely to perform rapid testing (74% vs. 47%, p < 0.0001), to use amantadine (88% vs. 48%, p < 0.0001), to restrict their prescribing to high-risk patients (86% vs. 53%, p < 0.0001), and to believe that antiviral therapy could decrease mortality (38% vs. 22%, p = 0.01). Other beliefs about antiviral therapy did not differ statistically between the specialties. Internists were more likely to be unfamiliar with rapid testing or not to have it available. CONCLUSION: Pediatricians and internists manage influenza differently. Evidence-based guidelines addressing the specific concerns of each group would be helpful.

Effects of local variation, specialty, and beliefs on antiviral prescribing for influenza.

In 2004, we conducted a survey of physician knowledge, attitudes, and practices regarding influenza diagnosis and treatment at Baystate Medical Center in Massachusetts and Scott & White Hospital and Clinic in Texas. Of the 579 physicians we contacted, 336 completed the survey. Sixty-one percent of the respondents prescribed antivirals, and 62% used rapid testing. Prescribing practices were associated with location, practice size, use of rapid testing, and belief in the efficacy of antivirals.

Management of influenza symptoms in healthy children: cost-effectiveness of rapid testing and antiviral therapy.

OBJECTIVE: To determine the cost-effectiveness of rapid testing and antiviral therapy for children of different ages with symptoms of influenza. DESIGN: Cost-effectiveness analysis from the societal perspective using a decision model based on published data. SETTING: Physician's office during an influenza A epidemic. PARTICIPANTS: Hypothetical children aged 2, 7, and 15 years. INTERVENTIONS: Rapid testing or clinical diagnosis followed by treatment with amantadine hydrochloride or oseltamivir phosphate compared with no antiviral therapy. OUTCOME MEASURES: Costs and quality-adjusted life expectancy. RESULTS: Empirical therapy with antiviral medication resulted in the greatest quality-adjusted life expectancy in all age groups. Compared with not treating, antiviral therapy improved quality-adjusted life expectancy by 0.003 quality-adjusted life-year by shortening the duration of illness and preventing otitis media. In young children it saved up to USD 121 per child mostly by avoiding parental work loss. Excluding work loss, antiviral therapy improved quality-adjusted life expectancy at a cost of USD 800 to 1800 per quality-adjusted life-year saved. Compared with amantadine, oseltamivir was not cost-effective when influenza A predominated. The incremental cost-effectiveness of oseltamivir fell below USD 50 000 per quality-adjusted life-year saved when the proportion of influenza B exceeded 14% for a 2-year-old, 27% for a 7-year-old, or 43% for a 15-year-old. Rapid testing was cost-effective only when the probability of influenza was 60% or less. CONCLUSIONS: For children presenting with influenza symptoms during a local influenza outbreak, treatment with antiviral therapy appears to offer the best outcome and often saves money. The choice of antiviral drug should be based on the prevalence of influenza B.

Improving nurse-to-patient staffing ratios as a cost-effective safety intervention.

BACKGROUND: Responding to research confirming the link between nurse staffing and patient outcomes, 14 states have introduced legislation to limit patient-to-nurse ratios. However, increased staffing places a considerable financial burden on hospitals. OBJECTIVE: We sought to determine the cost-effectiveness of various nurse staffing ratios. RESEARCH DESIGN: This was a cost-effectiveness analysis from the institutional perspective comparing patient-to-nurse ratios ranging from 8:1 to 4:1. Cost estimates were drawn from the medical literature and the Bureau of Labor Statistics. Patient mortality and length of stay data for different ratios were based on 2 large hospital level studies. Incremental cost-effectiveness was calculated for each ratio and sensitivity and Monte Carlo analyses performed. SUBJECTS: The study included general medical and surgical patients. MEASURES: : We sought to measure costs per life saved in 2003 US dollars. RESULTS OF BASE CASE ANALYSIS: Eight patients per nurse was the least expensive ratio but was associated with the highest patient mortality. Decreasing the number of patients per nurse improved mortality and increased costs, becoming progressively less cost-effective as the ratio declined from 8:1 to 4:1. Nonetheless, the incremental cost-effectiveness did not exceed US dollars 136,000 (95% CI US dollars 53,000-402,000) per life saved. RESULTS OF SENSITIVITY ANALYSIS: The model was most sensitive to the effects of patient-to-nurse ratios on mortality. Lower ratios were most cost-effective when lower ratios shortened length of stay, and hourly wages were low. However, throughout the ranges of all these variables, the incremental cost-effectiveness of limiting the ratio to 4:1 never exceeded US dollars 449,000 per life saved. CONCLUSIONS: As a patient safety intervention, patient-to-nurse ratios of 4:1 are reasonably cost-effective and in the range of other commonly accepted interventions.

Vaccination versus treatment of influenza in working adults: a cost-effectiveness analysis.

PURPOSE: To determine the cost-effectiveness of influenza vaccination, antiviral therapy, or no intervention for healthy working adults, accounting for annual variation in vaccine efficacy. METHODS: We conducted a cost-effectiveness analysis based on published clinical trials of influenza vaccine and antiviral drugs, incorporating 10 years of surveillance data from the World Health Organization. We modeled influenza vaccination, treatment of influenza-like illness with antiviral drugs, or both, as compared with no intervention, targeting healthy working adults under age 50 years in the general community or workplace. Outcomes included costs, illness days, and quality-adjusted days gained. RESULTS: In the base case analysis, the majority of costs incurred for all strategies were related to lost productivity from influenza illness. The least expensive strategy varied from year to year. For the 10-year period, antiviral therapy without vaccination was associated with the lowest overall costs (234 US dollars per person per year). Annual vaccination cost was 239 US dollars per person, and was associated with 0.0409 quality-adjusted days saved, for a marginal cost-effectiveness ratio of 113 US dollars per quality-adjusted day gained or 41,000 US dollars per quality-adjusted life-year saved compared with antiviral therapy. No intervention was the most expensive and least effective option. In sensitivity analyses, lower vaccination costs, higher annual probabilities of influenza, and higher numbers of workdays lost to influenza made vaccination more cost-effective than treatment. If vaccination cost was less than 16 US dollars or time lost from work exceeded 2.4 days per episode of influenza, then vaccination was cost saving compared with all other strategies. CONCLUSION: Influenza vaccination for healthy working adults is reasonable economically, and under certain circumstances is cost saving. Antiviral therapy is consistently cost saving.

Management of influenza symptoms in healthy adults.

OBJECTIVE: To determine the cost-effectiveness of rapid diagnostic testing and empiric antiviral therapy for healthy adults with symptoms of influenza. DESIGN: Cost-effectiveness analysis using a decision model based on previously published data. Outcome measures included costs and quality-adjusted life expectancy. SETTING: Physician's office. PATIENTS/PARTICIPANTS: Hypothetically healthy, working adults < 65 years of age presenting with cough and fever during the influenza season. INTERVENTIONS: Rapid testing or clinical diagnosis followed by treatment with amantadine, rimantadine, oseltamivir, or zanamivir compared with no antiviral therapy. RESULTS: Base-case analysis: not giving antiviral therapy is the most expensive and least effective strategy, costing 471 dollars per patient, mostly owing to time lost from work. Amantadine treatment increases life expectancy by 0.0014 quality-adjusted life years (QALYs) while saving 108 dollars per patient relative to no antiviral therapy. Zanamivir is slightly more effective than amantadine, adding 0.0002 QALYs at an incremental cost of 31 dollars, or 133,000 dollars per QALY saved. All other strategies, including testing strategies, are both less effective and more expensive. SENSITIVITY ANALYSIS: The model is sensitive to the probability of influenza infection, proportion of influenza caused by type B, the relative efficacy of the various drugs, and the value of a workday. At a clinical probability of influenza infection > 20%, antiviral therapy is favored. As the proportion of influenza B increases, zanamivir is favored over amantadine. Testing is rarely indicated. Ignoring the costs of lost workdays, amantadine treatment costs 1,200 dollars/QALY saved. CONCLUSIONS: Antiviral therapy with either amantadine or zanamivir is cost-effective for healthy, young patients with influenza-like illness during the influenza season, depending on the prevalence of influenza B.

Management of influenza in adults older than 65 years of age: cost-effectiveness of rapid testing and antiviral therapy.

BACKGROUND: Although antiviral therapy is cost-effective in adults, its cost-effectiveness in older adults has not been studied. OBJECTIVE: To determine the cost-effectiveness of influenza testing and treatment strategies for older adults. DESIGN: Cost-utility decision model. DATA SOURCES: Clinical trials of antiviral drugs and epidemiologic data. TARGET POPULATION: Noninstitutionalized adults older than 65 years of age with influenza-like illness. TIME HORIZON: Lifetime. PERSPECTIVE: Societal. INTERVENTIONS: Rapid diagnostic testing or empirical therapy with antiviral drugs. OUTCOME MEASURES: Cost per quality-adjusted life-year (QALY) saved. RESULTS OF BASE-CASE ANALYSIS: Compared with no intervention, empirically treating an unvaccinated 75-year-old patient with amantadine increased life expectancy by 0.0014 QALY at a cost of 1.57 dollars, a cost-effectiveness ratio of 1129 dollars per QALY saved. Compared with amantadine, rapid diagnostic testing followed by treatment with oseltamivir cost 5025 dollars per QALY saved and empirical treatment with oseltamivir cost 10,296 dollars per QALY saved. Testing and treatment strategies were less cost-effective if the patient was vaccinated, ranging from 2483 dollars per QALY saved with amantadine to 70,300 dollars per QALY saved with oseltamivir. RESULTS OF SENSITIVITY ANALYSIS: The decision was sensitive to the probability of influenza, the efficacy of oseltamivir in preventing hospitalizations, and hospitalization and case-fatality rates. The decision was not sensitive to the probability or severity of medication side effects, the quality of life for influenza illness or hospitalization, the efficacy of antiviral therapy in shortening influenza illness, or the rapid diagnostic test characteristics. CONCLUSIONS: For unvaccinated or high-risk vaccinated patients during the influenza season, empirical oseltamivir treatment is cost-effective. For other patients, rapid diagnostic testing followed by treatment with oseltamivir is cost-effective. Empirical amantadine treatment offers a low-cost alternative if patients cannot afford oseltamivir.

Is HIV infection a risk factor for complications of surgery?

BACKGROUND: The literature is inconsistent as to whether HIV-infected patients have higher rates of surgical complication rates than HIV-uninfected patients. This inconsistency reflects the failure to control for confounding variables in many of the previous studies. METHODS: A retrospective cohort study of records of HIV-infected individuals who underwent surgical procedures between 1990 and 1995 was matched with the records of HIV-uninfected control patients. We performed a logistic regression analysis to determine the independent effects of HIV infection and other potential risk factors for surgical complications. RESULTS: The crude rates of death and infectious and hematologic complications were higher among HIV-infected patients than among uninfected patients. Although the crude risk of having any complication was higher among the HIV-infected (odds ratio [OR]=2.47, p=0.015), the adjusted risk was not (OR=0.72 [p<0.613]). Variables significantly associated with complications were American Society of Anesthesiology (ASA) risk class (OR=2.7), age (OR=1.06 per year), and weight (OR=0.96 per kg). CONCLUSIONS: HIV sero-status was not found to be an independent risk factor for complications of surgery. The most important risk factor for complication of surgery in HIV-infected patients is ASA risk class.