Analysis of incidence and clinical characteristics of osteonecrosis of femoral head in patients with systemic lupus erythematosus treated with glucocorticoid: A descriptive study based on a prospective cohort / 中国修复重建外科杂志

OBJECTIVE@#To describe the disease characteristics of osteonecrosis of the femoral head (ONFH) in patients with systemic lupus erythematosus (SLE) who experiencing prolonged glucocorticoid (GC) exposure.@*METHODS@#Between January 2016 and June 2019, 449 SLE patients meeting the criteria were recruited from multiple centers. Hip MRI examinations were performed during screening and regular follow-up to determine the occurrence of ONFH. The cohort was divided into ONFH and non-ONFH groups, and the differences in demographic baseline characteristics, general clinical characteristics, GC medication information, combined medication, and hip clinical features were compared and comprehensively described.@*RESULTS@#The age at SLE diagnosis was 29.8 (23.2, 40.9) years, with 93.1% (418 cases) being female. The duration of GC exposure was 5.3 (2.0, 10.5) years, and the cumulative incidence of SLE-ONFH was 9.1%. Significant differences ( P<0.05) between ONFH and non-ONFH groups were observed in the following clinical characteristics: ① Demographic baseline characteristics: ONFH group had a higher proportion of patients with body mass index (BMI)<20 kg/m 2 compared to non-ONFH group. ② General clinical characteristics: ONFH group showed a higher proportion of patients with cutaneous and renal manifestations, positive antiphospholipid antibodies (aPLs) and anticardiolipin antibodies, severe SLE patients [baseline SLE Disease Activity Index 2000 (SLEDAI-2K) score ≥15], and secondary hypertension. Fasting blood glucose in ONFH group was also higher. ③ GC medication information: ONFH group had higher initial intravenous GC exposure rates, duration, cumulative doses, higher cumulative GC doses in the first month and the first 3 months, higher average daily doses in the first 3 months, and higher proportions of average daily doses ≥15.0 mg/d and ≥30.0 mg/d, as well as higher full-course average daily doses and proportion of full-course daily doses ≥30.0 mg/d compared to non-ONFH group. ④ Combined medications: ONFH group had a significantly higher rate of antiplatelet drug use than non-ONFH group. ⑤ Hip clinical features: ONFH group had a higher proportion of hip discomfort or pain and a higher incidence of hip joint effusion before MRI screening than non-ONFH group.@*CONCLUSION@#The incidence of ONFH after GC exposure in China's SLE population remains high (9.1%), with short-term (first 3 months), medium-to-high dose (average daily dose ≥15 mg/d) GC being closely associated with ONFH. Severe SLE, low BMI, certain clinical phenotypes, positive aPLs, and secondary hypertension may also be related to ONFH.

Influences of structural changes after valgus impacted femoral neck fracture on hip range of motion: a 3D simulation test / 中华创伤骨科杂志

Objective:To determine the influences of structural changes after valgus impacted femoral neck fracture on hip range of motion (ROM) so as to provide evidence for clinical judgment of whether reduction is necessary or not in the internal fixation of such fractures.Methods:1. 3D reconstructions of the CT hip scans were performed for the 73 patients who had been treated at Department of Orthopaedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University for valgus impacted femoral neck fractures from January 2019 to April 2019.The femoral neck-shaft angle, anteversion angle, femoral offset, axial alpha angle, lateral center edge angle (LCEA), anterior center edge angle (ACEA) and center displacement were measured and compared between the affected and healthy sides to determine the influences of the fracture on the above indexes. 2. Hip motions (flexion and MIR-90°) were simulated on bilateral sides to determine the influences of structural changes after fracture on hip ROM using stepwise regression and Logistic regression. 3. The distribution of femoral-acetabular contact points on the femoral side was observed in simulation of hip flexion to detect the potential area for femoracetabular impingement (FAI) induced by the fracture displacement.Results:1. The valgus impacted femoral neck fractures had significant influences on femoral neck-shaft angle, anteversion angle, femoral offset and axial alpha angle. Compared with the healthy side, on average, the femoral neck-shaft angle increased by 5.1°, anteversion angle decreased by 6.5°, femoral offset decreased by 8.2 mm and axial alpha angle increased by 9.7° on the affected side, showing significant differences ( P<0.05).The displacements of the femoral head center averaged 9.2 mm. There was no significant difference in LCEA or ACEA between the affected and healthy sides ( P>0.05). 2. Compared with the healthy side, on average, the simulated hip flexion decreased significantly by 27.0° and the hip MIR-90° decreased significantly by 20.3° on the affected side after fracture ( P<0.05). Regression analysis showed that femoral anteversion angle, ACEA and displacement of the femoral head center had a significant influence on hip ROM, especially the anteversion angle. When the anteversion angle decreased by more than 7.1°, the hip flexion would decrease by at least 20%. 3. The points of FAI distributed more widely on the fracture side. Compared with the healthy side, the impact points extended outward and upward in hip flexion and extended inwardly in hip MIR-90° on the affected side. Conclusions:After a valgus impacted femoral neck fracture, if the femoral anteversion angle has been decreased by more than 7.1°, the hip ROM can be greatly influenced and the points of FAI can be distributed more widely. Therefore, reduction should be recommended before internal fixation of the fracture.

The application of causal thinking in several issues in estimation of effects / 中华流行病学杂志

Epidemiology is a branch of science that mainly involves in the etiology studies of non-randomness phenomenon among homogenous populations. In this paper, we use causal-thinking, supported by its tool-Directed Acyclic Graphs, to illustrate how the estimation of effects is affected by the issues as relations between effect and association, time sequences between variables and their measured counterparts, natural picture of dynamic population, formation of susceptible population, selection of study population, impact of covariates and types of cases etc., on the estimation of effects. This type of thinking may help us to re-capture the epidemiological theories, methods and related applications. Thus, causal-thinking should be strengthened.

A structural classification of strategies for confounding control in research design / 中华流行病学杂志

Confounding affects the causal relation among the population.Depending on whether the confounders are known,measurable or measured,they can be divided into four categories.Based on Directed Acyclic Graphs,the strategies for confounding control can be classified as (1) the broken-confounding-path method,which can be further divided into single and dual broken paths,corresponding to exposure complete intervention,restriction and stratification,(2) and the reserved-confounding-path method,which can be further divided into incomplete exposure intervention (in instrumental variable design and non-perfect random control test),mediator method and matching method.Among them,random control test,instrumental variable design or Mendelian randomized design,mediator method can meet the requirements for controlling all four types of confounders,while the restriction,stratification and matching methods are only applicable to known,measurable and measured confounders.Identifying the mechanisms of confounding control is a prerequisite for obtaining correct causal effect estimates,which will be helpful in research design.

Exposure-preceding-outcome regarding time sequence among cohort studies in real world / 中华流行病学杂志

One of the commonly accepted merits of cohort studies (CSs) refers to the exposure precedes outcome superior to other observational designs.We use Directed Acyclic Graphs to construct a causal graph among research populations under CSs.We notice that the substitution of research population in place of a susceptible one can be used for effect estimation.Its correctness depends on the outcome-free status of the substituted population and the performance of both screening and diagnosis regarding the outcomes under study at baseline.The temporal precedence of exposure over outcome occurs theoretically,despite the opposite happens in realities.Correct effect estimate is affected by both the suitability of population substitution and the validities of outcome identification and exclusion.

Association and interaction of pre-pregnant body mass index and gestational weight gain of women on neonatal birthweight / 中华流行病学杂志

Objective To investigate the association between maternal pre-pregnant body mass index and gestational weight gain,as well as their interaction on neonatal birthweight.Methods We built a cohort in Anqing Municipal Hospital from January 2014 to March 2015,enrolling pregnant women who decided to give birth in this hospital.All women were asked to fill a questionnaire for basic information collection.Medical information of both pregnant women and their newborns were obtained through electronic medical record.Chi-square analysis,multinomial logistic regression,multiplicative and additive interaction methods were used to analyze the association between prepregnant body mass index and gestational weight gain as well as their interactions on birth weight of the neonates.Results A total of 2 881 pregnant women were included in this study.Of the 2 881 newborns,359 (12.46％) were small for gestational age (SGA) and 273 (9.48％) were large for gestational age (LGA).After adjusting the possible confounding factors,results from the multinomial logistic regression showed that pre-pregnancy underweight women were more possible to deliver SGA (aRR=1.33,95％CI:1.02-1.73).If the gestational weight gain was below the recommended criteria,the risk of SGA (aRR=1.64,95％ CI:1.23-2.19) might increase.Pre-pregnancy overweight/obese could increase the risk of being LGA (aRR=1.86,95％ CI:1.33-2.60).Maternal gestational weight gain above the recommendation level was associated with higher rates of LGA (aRR=2.03,95％CI:1.49-2.78).Results from the interaction analysis showed that there appeared no significant interaction between pre-pregnancy BMI and gestational weight on birthweight.Conclusion Pre-pregnancy body mass index and gestational weight gain were independently associated with neonatal birthweight while pre-pregnancy BMI and gestational weight gain did not present interaction on birthweight.

A structural classification of strategies for confounding control in research design / 中华流行病学杂志

Confounding affects the causal relation among the population.Depending on whether the confounders are known,measurable or measured,they can be divided into four categories.Based on Directed Acyclic Graphs,the strategies for confounding control can be classified as (1) the broken-confounding-path method,which can be further divided into single and dual broken paths,corresponding to exposure complete intervention,restriction and stratification,(2) and the reserved-confounding-path method,which can be further divided into incomplete exposure intervention (in instrumental variable design and non-perfect random control test),mediator method and matching method.Among them,random control test,instrumental variable design or Mendelian randomized design,mediator method can meet the requirements for controlling all four types of confounders,while the restriction,stratification and matching methods are only applicable to known,measurable and measured confounders.Identifying the mechanisms of confounding control is a prerequisite for obtaining correct causal effect estimates,which will be helpful in research design.

Exposure-preceding-outcome regarding time sequence among cohort studies in real world / 中华流行病学杂志

One of the commonly accepted merits of cohort studies (CSs) refers to the exposure precedes outcome superior to other observational designs.We use Directed Acyclic Graphs to construct a causal graph among research populations under CSs.We notice that the substitution of research population in place of a susceptible one can be used for effect estimation.Its correctness depends on the outcome-free status of the substituted population and the performance of both screening and diagnosis regarding the outcomes under study at baseline.The temporal precedence of exposure over outcome occurs theoretically,despite the opposite happens in realities.Correct effect estimate is affected by both the suitability of population substitution and the validities of outcome identification and exclusion.

Association and interaction of pre-pregnant body mass index and gestational weight gain of women on neonatal birthweight / 中华流行病学杂志

Objective To investigate the association between maternal pre-pregnant body mass index and gestational weight gain,as well as their interaction on neonatal birthweight.Methods We built a cohort in Anqing Municipal Hospital from January 2014 to March 2015,enrolling pregnant women who decided to give birth in this hospital.All women were asked to fill a questionnaire for basic information collection.Medical information of both pregnant women and their newborns were obtained through electronic medical record.Chi-square analysis,multinomial logistic regression,multiplicative and additive interaction methods were used to analyze the association between prepregnant body mass index and gestational weight gain as well as their interactions on birth weight of the neonates.Results A total of 2 881 pregnant women were included in this study.Of the 2 881 newborns,359 (12.46％) were small for gestational age (SGA) and 273 (9.48％) were large for gestational age (LGA).After adjusting the possible confounding factors,results from the multinomial logistic regression showed that pre-pregnancy underweight women were more possible to deliver SGA (aRR=1.33,95％CI:1.02-1.73).If the gestational weight gain was below the recommended criteria,the risk of SGA (aRR=1.64,95％ CI:1.23-2.19) might increase.Pre-pregnancy overweight/obese could increase the risk of being LGA (aRR=1.86,95％ CI:1.33-2.60).Maternal gestational weight gain above the recommendation level was associated with higher rates of LGA (aRR=2.03,95％CI:1.49-2.78).Results from the interaction analysis showed that there appeared no significant interaction between pre-pregnancy BMI and gestational weight on birthweight.Conclusion Pre-pregnancy body mass index and gestational weight gain were independently associated with neonatal birthweight while pre-pregnancy BMI and gestational weight gain did not present interaction on birthweight.

Clinical Observation and Bacteriostatic Study on Axiong Powder, a Traditional Drug of Miao Nationality / 中医杂志

Axiong Powder is a powdered drug applied by Miao people for the treatment and prevention of URI ( upper respiratory infection) , hemorrhoid, carbuncles and boils. Preliminary analysis revealed it to contain some ten kinds of herbs. By clinical analysis, it was shown that the Powder yields rather good therapeutic results on cold, tonsillitis, pyogenic tonsillitis, contusion, sprain. Bacteria strainisolated clinically can be inhibited by Axiong water decoction.