The PRECIS-2 tool: designing trials that are fit for purpose / 中华流行病学杂志

To evaluate the intervention effects of randomized controlled trials (RCT) involved in theoretical efficacy and actual clinical outcome (effectiveness). Pragmatic-Explanatory Continuum Indicator Summary (PRECIS) is a tool to help researchers make decisions in study design which is consistent with the intended purpose of their trial which can be used in the design of RCT to balance the internal validity and external validity. The role of PRECIS has been gradually recognized in the practice of designing clinical trials. To ensure that the design choices are concordant with the intention and the facilitation of use set by patients, clinicians and policy makers, a new PRECIS-2 tool has been developed by mangy international team experts under modification and upgrading the existing PRECIS. The PRECIS-2 tool mainly focuses on trial design choices which determining the applicability of a trial. PRECIS-2 has nine domains, with each of them intends to help the researchers consider the consequences of that design decision in terms of the applicability of the results under particular setting. The purpose of this paper is to introduce the development, basic principle, characteristics and application of PRECIS-2 for the designers and decision makers when working on clinical trials.

Seasonal distribution of patient hospitalization due to asthma exacerbation in 7 geographic areas in China / 中华流行病学杂志

Objective: To understand the seasonal distribution of patient hospitalization due to asthma exacerbation in 7 geographic areas in China. Methods: This was a retrospective study which involved patients hospitalized for asthma exacerbation in 29 hospitals throughout 7 geographic areas in the mainland of China (northeast, north, central, east, south, northwest and southwest). The numbers of asthmatic patients and total inpatients of the respiratory department of each hospital were recorded. The monthly ratio of asthmatic patients to the total inpatients in every area was calculated and compared. Results: During the study period, 6 480 patients were admitted for asthma exacerbation, accounting for 3.14% of all the 206 135 patients admitted to the respiratory departments in the 29 hospitals. The ratio of asthmatic patients to total inpatients in the northeast area (5.61%) was highest, and the ratio in east area was lowest (1.97%). Statistical analysis showed that the difference among different areas was significant (P<0.000 1). In most areas, both the number and proportion of hospitalized asthmatic patients peaked in spring (February-April) and autumn (September-October). In the northeast area, east area and south area, the peaks in spring were more obvious, while in the north area and southwest area, the peaks in autumn were more obvious. In the northwest area the peaks occurred in winter (December-January) and summer (June-August), respectively. The differences in hospitalization due to asthma among different months were significant in the northeast, north, and southwest areas (P<0.005). Conclusion: The number of patients hospitalized for asthma exacerbation fluctuated with season in different areas in China. In most areas, more asthmatic patients were admitted to hospitals in spring and autumn.

Environmental behavior of pahs in dianchi lake distributions, sources and risk assessment of poly cyclic aromatic hydrocarbons in surface sediments from Dianchi Lake,China

Polycyclic aromatic hydrocarbons [PAHs] in the priority controlling list of US EPA were systematically evaluated in surface sediments in Dianchi Lake and its estuaries. Total PAH concentrations [IPAHs] varied from 210 to 11,070 ng/gdry weight [d.w] in Dianchi Lake, and from 230 to 12,271 microg/g d.w. in the estuaries. IPAHs in sediments from Caohai section were higher than those from Waihai section. The occurrences of PAHs in the Lake were closely related to the distributions of rivers, indicating that the river runoff was an important pathway of PAHs into the Lake. Compared with the US Sediment Quality Guidelines [SQGs], IPAHs in most area were below the effect range low [ERL], which implied that the adverse biological effects would occur rarely. The toxic equivalent concentrations of potentially carcinogenic PAHs [TEQ[carc]] varied from 19to967ngTEQ/gd.w., and the higher values were found in northern Caohai area. The proportions of the toxic equivalent quantity [TEQ[carc]] to the total TEQs in sediments were all above 96%, suggesting that the carcinogenicity of PAHs could be occurred. Significantly positive correlations between total organic carbon [TOC] and less molecular weight PAHs [2, 3-ring] [LPAHs] were observed in the Lake. Diagnostic ratios showed that the primary source of PAHs in Dianchi Lake and most estuaries is biomass combustion, but is petroleum combustion or petrogenic origin in several other estuaries