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Abstract Background Incremental value (IncV) evaluates the performance change between an existing risk model and a new model. Different IncV metrics do not always agree with each other. For example, compared with a prescribed-dose model, an ovarian-dose model for predicting acute ovarian failure has a slightly lower area under the receiver operating characteristic curve (AUC) but increases the area under the precision-recall curve (AP) by 48%. This phenomenon of disagreement is not uncommon, and can create confusion when assessing whether the added information improves the model prediction accuracy. Methods In this article, we examine the analytical connections and differences between the AUC IncV (ΔAUC) and AP IncV (ΔAP). We also compare the true values of these two IncV metrics in a numerical study. Additionally, as both are semi-proper scoring rules, we compare them with a strictly proper scoring rule: the IncV of the scaled Brier score (ΔsBrS) in the numerical study. Results We demonstrate that ΔAUC and ΔAP are both weighted averages of the changes (from the existing model to the new one) in separating the risk score distributions between events and non-events. However, ΔAP assigns heavier weights to the changes in higher-risk regions, whereas ΔAUC weights the changes equally. Due to this difference, the two IncV metrics can disagree, and the numerical study shows that their disagreement becomes more pronounced as the event rate decreases. In the numerical study, we also find that ΔAP has a wide range, from negative to positive, but the range of ΔAUC is much smaller. In addition, ΔAP and ΔsBrS are highly consistent, but ΔAUC is negatively correlated with ΔsBrS and ΔAP when the event rate is low. Conclusions ΔAUC treats the wins and losses of a new risk model equally across different risk regions. When neither the existing or new model is the true model, this equality could attenuate a superior performance of the new model for a sub-region. In contrast, ΔAP accentuates the change in the prediction accuracy for higher-risk regions.

Providing accurate and dynamic age-specific risk prediction is a crucial step in precision medicine. In this manuscript, we introduce an approach for estimating the τ-year age-specific absolute risk directly via a flexible varying coefficient model. The approach facilitates the utilisation of predictors varying over an individual's lifetime. By using a nonparametric inverse probability weighted kernel estimating equation, the age-specific effects of risk factors are estimated without requiring the specification of the functional form. The approach allows borrowing information across individuals of similar ages, and therefore provides a practical solution for situations where the longitudinal information is only measured sparsely. We evaluate the performance of the proposed estimation and inference procedures with numerical studies, and make comparisons with existing methods in the literature. We illustrate the performance of our proposed approach by developing a dynamic prediction model using data from the Framingham Study.

Mengcao Weng,1,&ast; Dongdong Wang,2,&ast; Jia Zhong,2 Minyue Qian,1 Kai Zhang,2 Yue Jin1 1Department of Anesthesiology, Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang, People’s Republic of China; 2Department of Anesthesiology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Yue Jin, Department of Anesthesiology, Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Rd, Hangzhou, Zhejiang, 310052, People’s Republic of China, Tel +8613456912018, Email yue_jin@zju.edu.cn Kai Zhang, Department of Anesthesiology, the First Affiliated Hospital, Zhejiang University School of Medicine, Wenyixi Road 1367, Hangzhou, 311121, People’s Republic of China, Tel +8615858281107, Email comezk@zju.edu.cnPurpose: This study aimed to establish the 95% effective dose (ED95) of esketamine in combination with propofol for hysteroscopy and then to evaluate its efficacy and safety profile.Patients and Methods: This prospective, double-blind, randomized controlled trial consisted of two cohorts. In cohort 1, 45 women aged 18– 65 years undergoing hysteroscopy were randomly assigned to either group E (esketamine + propofol) or group A (alfentanil + propofol). Dixon’s up-and-down method was used to determine the ED95 of esketamine and alfentanil. In cohort 2, 86 patients were randomized to group E and group A, with the calculated ED95 dose of the study drugs used for induction. The success rate of anesthesia using the ED95% dose, along with parameters related to anesthesia induction, recovery, and adverse events were also recorded.Results: The ED95 of esketamine was 0.254 mg/kg (95% CI: 0.214– 1.004), while that of alfentanil was 9.121 μg/kg (95% CI: 8.479– 13.364). The anesthesia success rate was 93.0% in group E and 95.2% in group A (p = 0.664). After resuscitation, both groups achieved a 100% success rate. The induction time was significantly shorter in group E (60.0 [55.0– 70.0] s) compared to group A (67.0 [61.0– 79.3] s) (p = 0.006). Group E had lower rates of respiratory depression (p < 0.001), hypoxia (p = 0.006), minimum perioperative SpO2 (p = 0.010), and hypotension (p = 0.001). Esketamine had less effect on respiratory rate, heart rate, mean blood pressure, and end-tidal carbon dioxide compared to alfentanil (all p < 0.001). There were no significant differences in postoperative pain between the two groups.Conclusion: This study determined the ED 95 dose of esketamine for intravenous general anesthesia during hysteroscopy. Esketamine showed less respiratory and hemodynamic depression, as well as fewer adverse effects compared to alfentanil. Esketamine is an ideal anesthetic agent compared to alfentanil for hysteroscopic anesthesia.Trial Registration: www.chictr.org.cn, (ChiCTR2300077283); registered November 3, 2023.Keywords: esketamine, 95% effective dose, hysteroscopy, propofol

Xinjian Kang,1,2 Man Qian,3 Mingli Liu,2 Haiwei Xu,4 Baoshan Xu4 1Department of Orthopedics, Traditional Chinese Medicine Hospital of Qinhuangdao, Qinhuangdao, Hebei, People’s Republic of China; 2Tianjin Medical University, Graduate School, Tianjin, People’s Republic of China; 3Department of Refractive Surgery, Qinhuangdao Aier Ophthalmic Hospital, Qinhuangdao, Hebei, People’s Republic of China; 4Department of Minimally Invasive Spine Surgery, Tianjin Hospital, Tianjin, People’s Republic of ChinaCorrespondence: Baoshan Xu, Department of Minimally Invasive Spine Surgery, Tianjin Hospital, No. 406 Jiefangnan Road, Hexi District, Tianjin, People’s Republic of China, Tel +86 13502028198, Fax +86- 22 -28241184, Email baoshanxu99@tmu.edu.cnPurpose: To explore the predictive factors of neck pain (NP) in patients with cervical degenerative disease by retrospectively analyzing their occupational and demographic characteristics and to provide a valuable reference for preventing and treating chronic NP.Patients and Methods: We retrospectively reviewed the occupational and demographic data of patients with cervical degenerative disease who had undergone anterior cervical surgery between June 2021 and December 2022 at our center. The patients were divided into NP and no-NP groups based on whether they had chronic NP before surgery. Relevant occupational and demographic data from all patients were statistically analyzed, and all variables were made categorical. Forward stepwise logistic regression models were constructed for preoperative chronic neck pain to explore the possible risk factors associated with chronic neck pain.Results: The differences in smoking, being an office worker, BMI, and disease types between NP and no-NP groups were statistically significant. In contrast, there were no statistically significant in age, sex, academic level, duration, and degeneration grade between the two groups. Moreover, further logistic regression analysis indicated that smoking, being an office worker, having an abnormal BMI, and cervical spondylotic radiculopathy (CSR) were related to chronic neck pain.Conclusion: The present study indicated that smoking, being an office worker, having an abnormal BMI, and CSR were predisposing risk factors for NP associated with cervical degenerative disease. Although intervertebral disc degeneration is the pathology basis of NP, the degeneration grade was not related to the occurrence of NP in our current study. Therefore, quitting smoking, avoiding sedentariness, and maintaining a normal BMI may prevent NP to some extent.Keywords: discogenic pain, radiating pain, musculoskeletal disorder, intervertebral disc degeneration

© 2020 Elsevier B.V. The energy consumption of air-conditioning systems has gained increasing attention as it contributes significantly to the global building energy use. The variable refrigerant flow (VRF) system is a common air-conditioning system applied widely in residential and office buildings in China. Understanding the actual operation and performance of VRF systems is fundamental for the energy-efficient design and operation of VRF systems. Previous research on VRF system operation used either limited field data covering certain building types and climate zones or used a questionnaire to obtain a larger dataset. However, they did not capture the wide applications of VRF systems quantitatively across all building types, climate zones, and operating conditions. To fill this gap, statistical and clustering analysis was conducted on the newly proposed key performance indicators of approximately 287,000 VRF systems for residential and commercial buildings in all five climate zones in China. The main findings are: (1) VRF systems are mainly used for cooling in all climate zones in China; (2) among all building types, the duration of use is lowest in residential buildings and highest in hotels and medical buildings; (3) the distribution of the ideal VRF cooling coefficient of performance (COP) is similar across all climate zones and building types; whereas the COPs of ideal VRF heating in the Severe Cold region and Cold regions are lower than those in other climate zones; and (4) partial load operations for VRF systems are common in residential buildings and office buildings due to the part-time-part-space operation mode. These findings can inform the actual application of VRF systems in China, supporting the design, operation, industry standard development, and performance optimization of VRF systems.

Prediction performance of a risk scoring system needs to be carefully assessed before its adoption in clinical practice. Clinical preventive care often uses risk scores to screen asymptomatic population. The primary clinical interest is to predict the risk of having an event by a prespecified future time t0 . Accuracy measures such as positive predictive values have been recommended for evaluating the predictive performance. However, for commonly used continuous or ordinal risk score systems, these measures require a subjective cutoff threshold value that dichotomizes the risk scores. The need for a cutoff value created barriers for practitioners and researchers. In this paper, we propose a threshold-free summary index of positive predictive values that accommodates time-dependent event status and competing risks. We develop a nonparametric estimator and provide an inference procedure for comparing this summary measure between 2 risk scores for censored time to event data. We conduct a simulation study to examine the finite-sample performance of the proposed estimation and inference procedures. Lastly, we illustrate the use of this measure on a real data example, comparing 2 risk score systems for predicting heart failure in childhood cancer survivors.