How profitable is risk selection? A comparison of four risk adjustment models

To mitigate selection triggered by capitation payments, risk-adjustment models bring capitation payments closer on average to individuals' expected expenditure. We examine the maximum potential profit that plans could hypothetically gain by using their own private information to select low-cost enrollees when payments are made using four commonly used risk adjustment models. Simulations using a privately insured sample suggest that risk selection profits remain substantial. The magnitude of potential profit varies according to the risk adjustment model and the private information plans can employ to identify profitable enrollees.     

Can a decline in the population means of cardiovascular risk factors reduce the number of people at risk?

OBJECTIVE: To prove the possibility of shifting distribution of cardiovascular risk factors for a whole population over time and thereby to influence the prevalence of the corresponding disease states, according to the theory stated by Geoffrey Rose in 1985. DESIGN: Examination of standardised data from the German Cardiovascular Prevention Study (GCP), a seven year long, population-based, multicentre intervention trial, concerned with decreasing risk factors for cardiovascular disease. SETTING AND SUBJECTS: three cross sectional surveys of a population 25 to 69 years old in six study regions, and three nationwide cross sectional surveys in the former West Germany in 1984, 1988 and 1991. MAIN OUTCOME MEASURES: The relation between the population mean for systolic and diastolic blood pressure, total serum cholesterol, body mass index, and alcohol intake, and the prevalence of the corresponding disease states, as are systolic (> or =140 and > or =160 mm Hg) and diastolic hypertension (> or =90 and > or =95 mm Hg), hypercholesterolaemia (> or =250 and > or =300 mg/dl), overweight (body mass index > or =30 kg/m2), and heavy drinking (weekly alcohol intake > or =300 g/week). Results are expressed as linear regression equations and Pearson correlation coefficients. RESULTS: The correlation between the mean population values and prevalence of disease was close for blood pressures and body mass index. The Pearson coefficients, corrected for the influence of values increased above borderlines, were 0.86 and 0.81 respectively for systolic blood pressure, 0.88 and 0.91 for diastolic blood pressure, 0.28 and 0.52 for cholesterol, and 0.86 for the body mass index. The coefficient for alcohol intake was 0.55. CONCLUSIONS: It seems possible to shift the risk distribution of a population for some physiological parameters over time with the effect of changing the disease prevalence. This strategy can be used successfully for specific preventive measures, as was strongly advocated by Geoffrey Rose.     

Critiques of the risk concept--valid or not?

The increasing use of the risk concept in healthcare has caused concern among medical doctors, especially general practitioners (GPs). Critics have claimed that risk identification and intervention create unfounded anxiety, that the concept of risk is not useful at the individual patient level, that patients' risk concept is different from an epidemiological one, that resources are better spent elsewhere, or that commercial interests take advantage of risk information to promote sales. In this paper the authors discuss the concept of risk and address the critique. There is evidence that commercial interests promote risk interventions, that patients may misunderstand risk information, and that risk information can cause unnecessary anxiety. The authors have found no empirical data on the amount of time primary healthcare providers spend on risk interventions, and have not identified any valid arguments that risk information is not useful for the individual patient. Decision-making under uncertainty is a core element of medical practice, and GPs need to be suitably trained to inform patients such that they make good decisions when they are faced with uncertainty. The concept of risk is therefore useful for GPs, and in fact a key issue. It is concluded that risk critique should be based on sound theory and empirical data. Critics may do well in making clear distinctions between facts and value judgements.     

Evaluation of risk of thrombosis during use of low-dose ethinylestradiol—desogestrel oral contraceptive

Thirty healthy young women, non-smokers and of normal weight, used a combined oral contraceptive consisting of 20 g ethinylestradiol and 150 g desogestrel for 9 cycles. Before and during the 3rd, 6th and 9th cycles of contraceptive use, the following parameters were measured: triglycerides, total cholesterol, HDL-cholesterol, apolipoprotein A and B, prothrombin time, partial thromboplastin time, fibrinogen, antithrombin III, protein C, plasminogen, antiplasmin, tissue plasminogen activator, platelet count, platelet aggregation, -thromboglobulin and platelet factor 4. The ratios of total cholesterol/HDL-cholesterol and apolipoprotein A/B remained constant or showed only a slight increase. The clotting/fibrinolytic balance showed a similar trend. There was however, an inconstant but significant increase in antithrombin III and protein C. Platelet count and platelet function parameters were unmodified. Hence the contraceptive induced no substantial changes in lipid balance or blood clotting, at least during the study period.

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Resumen Treinta mujeres jóvenes, en buen estado de salud, no fumadoras y de peso normal, utilizaron durante 9 ciclos un anticonceptivo oral combinado de 20 g de etinilestradiol y 150 g de desogestrel. Antes y durante los ciclos tercero, sexto y noveno de utilización de este anticonceptivo, se midieron los siguientes parámetros: triglicéridos, colesterol total, colesterol HDL, apolipoproteína A y B, tiempo de protrombina, timepo de tromboplastina parcial, fibrinógeno, antitrombina III, proteína C, plasminógeno, antiplasmina, activador plasminógeno tisular, recuento de plaquetas, agregación de plaquetas, -tromboglobulina y factor 4 de las plaquetas. Las relaciones colesterol total/colesterol HDL y apolipoproteína A/B permanecieron constantes o bien mostraron un ligero aumento. Se observó la misma tendencia en el equilibrio coagulación/fibrinólisis. Sin embargo, se observó un aumento no constante pero significativo de la antitrombina III y la proteína C. El recuento de plaquetas y los parámetros de función de las plaquetas no sufrieron modificaciones. En consecuencia, el anticonceptivo no provocó ningún cambio importante en el equilibrio de los lípidos o en la coagulación de la sangre, al menos durante el período de estudio.

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Resumé Trente jeunes femmes en bonne santé, non fumeuses et de pids normal, ont utilisé durant 9 cycles un contraceptif oral combiné de 20 g d'éthinyloestradiol et 150 g de désogestrel. Avant et pendant les troisième, sixième et neuvième cycles de l'utilisation de ce produit, on a mesuré les paramètres suivants: triglycérides, cholestérol total, cholestérol-HDL, apolipoprotéines A et B, temps de prothrombine, temps de thromboplastine, fibrinogène, antithrombine III, protéine C, plasminogène, antiplasmine, plasmonigène-proactivateur, numération des plaquettes, agrégation des plaquettes, thromboglobuline- et facteur 4 des plaquettes. Les rapports cholestérol total/cholestérol-HDL et apolipoprotéines A/B sont restés constants ou ont légèrement augmenté. On a observé la même tendance pour l'équilibre coagulation/fibrinolyse. On a cependant constaté une hausse inconstante mais significative de l'antithrombine III et des protéines C. La numération des plaquettes et les paramètres de la fonction plaquettaire sont restés inchangés. Le contraceptif n'a donc provoqué aucun changement important de l'équilibre des lipides ou de la coagulation sanguine, pour le moins durant la période d'étude.

     

Does ozonation of drinking water reduce the risk of bladder cancer?

BACKGROUND: Epidemiologic studies of drinking water disinfection byproducts have focused primarily on the carcinogenic potential of chlorination byproducts. Because drinking water has been ozonated in France for decades, we were able to assess the carcinogenic risk of the disinfection byproducts generated by both ozonation and chlorination. METHODS: We used data from a case-control study of bladder cancer conducted between 1985 and 1987 in 7 French hospitals. We compared 281 cases and 272 controls for whom we could reconstruct at least 70% of the residential exposure to drinking water contaminants over a 30-year period. RESULTS: When we took potential confounders and exposure to chlorination byproducts into account, the risk of bladder cancer decreased as duration of exposure to ozonated water increased (OR = 0.60 [95% CI = 0.3-1.3] for 1-9 years; OR = 0.31 [0.1-0.7] for 10 years or more). Simultaneously, the risk of bladder cancer increased with duration of exposure to chlorinated surface water and with the estimated trihalomethane content of the water. Our data suggest that ozonation reduces the risk associated with the chlorination of surface water and that ozonation alone could have an independent beneficial effect on bladder cancer risk. CONCLUSIONS: Our results are consistent with experimental evidence that ozonation in combination with chlorination decreases the concentration of trihalomethane in treated water and eliminates some of the mutagenicity of raw water.     

Does alcohol increase the risk of preterm delivery?

We evaluated the association between alcohol intake during pregnancy and preterm delivery. Women attending routine antenatal care at Aarhus University Hospital, Denmark, from 1989-1991 and 1992-1996 were eligible. We included 18,228 singleton pregnancies in the analyses. We obtained prospective information on alcohol intake at 16 and 30 weeks of gestation, other lifestyle factors, maternal characteristics, and obstetrical risk factors from self-administered questionnaires and hospital files. For women with alcohol intake of 1-2, 3-4, 5-9, and > or =10 drinks/week the risk ratio (RR) of preterm delivery was 0.91 (95% CI = 0.76-1.08), 0.86 (95% CI = 0.64-1.15), 0.89 (95% CI = 0.52-1.52), and 2.93 (95% CI = 1.52-5.63), respectively, compared with intake of <1 drink/week at 16 weeks gestation, and 0.69 (95% CI = 0.56-0.86), 0.82 (95% CI = 0.60-1.13), 0.97 (95% CI = 0.58-1.64), and 3.56 (95% CI = 1.78-7.13) at 30 weeks. Adjustment for smoking habits, caffeine intake, age, height, pre-pregnant weight, marital status, occupational status, education, parity, chronic diseases, previous preterm delivery, mode of initiation of labor, and sex of the child did not change the conclusions, nor did restriction of the highest intake group to women drinking 10-14 drinks/week (RR = 3.41 (1.71-6.81) at 16 weeks and RR = 3.47 (1.64-7.35) at 30 weeks).     

Does appendectomy reduce the risk of ulcerative colitis?

BACKGROUND: Persons who have had an appendectomy are less prone to develop ulcerative colitis than those who have not. The underlying mechanism and the clinical use of this finding are unknown. METHODS: Two competing hypotheses were examined: (1) the inverse association between appendectomy and ulcerative colitis is conferred by a mutual determinant such as genes, and (2) the appendix itself has biologic effects that promote the development of ulcerative colitis. We performed a population-based cohort study of all 234,559 persons who had an appendectomy performed in Denmark 1977 through 1999. We used a bidirectional cohort design, calculating the standardized incidence rate of ulcerative colitis both before and after the appendectomy. If the hypothesis of a constant, confounding factor were true, incidence rates of ulcerative colitis would be equal before and after appendectomy. If the incidence of ulcerative colitis were lower after appendectomy than before, it would support the second hypothesis and a true protective effect of the appendectomy. We controlled confounding by age and sex using direct standardization. RESULTS: Of 234,559 persons who had an appendectomy, 559 developed ulcerative colitis during a mean follow up of 17.5 years. The standardized incidence rate of ulcerative colitis was lower in the postappendectomy period than in the preappendectomy period (incidence rate ratio = 0.74; 95% confidence interval = 0.62-0.88). CONCLUSIONS: The inverse association between appendectomy and ulcerative colitis is not explained by time-stable factors such as genes. Appendectomy might have a genuine protective effect toward development of ulcerative colitis.     

Mild dehydration: a risk factor of constipation?

Constipation defined as changes in the frequency, volume, weight, consistency and ease of passage of the stool occurs in any age group. The most important factors known to promote constipation are reduced physical activity and inadequate dietary intake of fibres, carbohydrates and fluids. Fluid losses induced by diarrhoea and febrile illness alter water balance and promote constipation. When children increase their water consumption above their usual intake, no change in stool frequency and consistency was observed. The improvement of constipation by increasing water intake, therefore, may be effective in children only when voluntary fluid consumption is lower-than-normal for the child's age and activity level. In the elderly, low fluid intake, which may be indicative of hypohydration, was a cause of constipation and a significant relationship between liquid deprivation from 2500 to 500 ml per day and constipation was reported. Dehydration is also observed when saline laxatives are used for the treatment of constipation if fluid replacement is not maintained and may affect the efficacy of the treatment. While sulphate in drinking water does not appear to have a significant laxative effect, fluid intake and magnesium sulphate-rich mineral waters were shown to improve constipation in healthy infants. In conclusion, fluid loss and fluid restriction and thus de-or hypohydration increase constipation. It is thus important to maintain euhydration as a prevention of constipation.     

Assessment of global cardiovascular risk and risk factors in Portugal according to the SCORE® model

Background/objective

Cardiovascular diseases (CVD) are the leading cause of mortality in European countries. This study aimed at estimating the 10-year risk of fatal CVD in Portuguese adults and to assess the prevalence of major cardiovascular risk factors, according to the SCORE® risk prediction system.

Subjects and methods

A cross-sectional survey was carried out in 60 community pharmacies (CP) from October 2005 to January 2006 in a sample of CP users (≥40 and ≤65 years). Data were collected by patient interviews using a structured questionnaire applied by a trained pharmacist.

Results

A total of 1,043 individuals were enrolled in the study (participation rate: 91%). The mean age was 53.7 years (SD: 7.1) with a ratio men/women of 0.68. The average risk in the sample was 1.94 (minimum 0, maximum 28, SD?=2.69). About 20% of the studied adults were at high risk, of which 39.4% were asymptomatic. CV risk was significantly higher in the oldest age group and in men (p?2): 28.0?±?4.5.

Conclusions

According to SCORE®, about one-fifth of the individuals was classified as high risk, and 7.7% was asymptomatic. CV risk was significantly higher in the oldest age group (55–65 years old) and in men (p?     

Does asbestos exposure increase the risk of urogenital cancer?

Summary The risk of urogenital cancer to workers exposed to asbestos was evaluated using the results of published studies. The pooled standardized mortality ratios (SMRs), based on the results of cohort studies, were significantly increased (P0.05) for ovarian and kidney cancer in North American studies but not in other studies. Part of these increases probably is due to the use of inappropriate comparison populations and the failure to take into account risk factors associated with urogenital cancer. Other types of studies generally did not indicate that exposure to asbestos increases the risk of urogenital cancer. Generally, there is insufficient information to show that urogenital cancers are caused by occupational exposure to asbestos.