Background: Extremely low birth weight (ELBW, <1,000 g) infants have a high risk of metabolic bone disease (MBD). Because of the late appearance of radiological signs, diagnosis of MBD in ELBW infants might be delayed, and its prevalence underestimated in this group of patients. This study adopted serial screening of serum alkaline phosphatase (ALP) and phosphate (P) of ELBW infants to determine whether such screening is helpful for the early detection of MBD.Materials and Methods: We performed a retrospective study of preterm infants with a gestational age ≤ 31 weeks and birth weight <1,000 g. MBD was absent (ALP ≤500 IU/L), mild (ALP >500 IU/L, P ≥4.5 mg/dL), and severe (ALP >500 IU/L, P <4.5 mg/dL); MBD was divided into early MBD (≤4 weeks after birth) and late MBD (>4 weeks after birth) according to the time of onset.Results: A total of 142 ELBW infants were included, with a median gestational age of 28.1 (26.5–29.7) weeks and a median birth weight of 875 (818–950) g. Seventy-three cases of MBD were diagnosed, and the total prevalence was 51.4% (mild MBD, 10.6%; and severe MBD, 40.8%). Male sex, breastfeeding, and sepsis would increase the risk of severe MBD. Most MBD in ELBW infants occurred at 3–4 weeks after birth. Sixty-two percent (45/73) of infants were diagnosed as having early MBD, which are diagnosed earlier than late MBD [24 (21–26) vs. 39 (36–41), t = −7.161; P < 0.001]. Male sex [odds ratio (OR), 2.86; 95% confidence interval (CI), 1.07–7.64; P = 0.036], initial high ALP levels (OR, 1.02; 95% CI, 1.01–1.03; P < 0.001), and breastfeeding (OR, 5.97; 95% CI, 1.01–25.12; P = 0.049) are independent risk factors for the development of early MBD.Conclusion: The risk of MBD among ELBW infants is very high. Most cases occurred early and were severe. Male sex, initial high ALP levels, and breastfeeding are closely related to the increased risk of early MBD. Serial screening of serum ALP and P helps early detection of MBD; it is recommended to start biochemical screening for ELBW infants 2 weeks after birth and monitor their biochemical markers weekly.

Background: Delirium is a common postoperative complication of total hip arthroplasty (THA), excessively long time surgery may be one of the factors associated with it. This article aimed to employ literature retrieval and meta-analysis to investigate the correlation between operation time and postoperative delirium in THA. Methods:The databases of PubMed and Springerlink libraries were searched for retrospective casecontrol studies on delirium-related factors after THA. The retrieved studies were screened according to the inclusion criteria. Newcastle-Ottawa scale (NOS) was used to assess the quality of literatures. After extracting the data of included literatures, RevMan 5.3.5 software was used to analyze the data and obtain a forest plot and funnel plot.Results: A total of 137 literatures were initially screened in this study. According to the inclusion and exclusion criteria and literature quality evaluation, 6 studies were finally included, involving a total of 3,494 patients. The NOS scores were above 6 points in all 6 literatures. Meta-analysis revealed statistical heterogeneity among the 6 studies (I 2 =80%, P=0.0002). The random effects model was used, revealing that the operation time of patients with postoperative delirium was longer, and the difference was statistically significant [standardized mean difference (SMD) =0.43, 95% confidence interval (CI): 0.20 to 0.66, P=0.0003]. The 6 studies were divided into unilateral or bilateral THA subgroups according to the type of surgery. Homogeneity was detected between the internal literatures: bilateral subgroup (I 2 =5%, P=0.37), unilateral subgroup (I 2 =0%, P=0.78). Postoperative delirium was associated with longer operation time in both subgroups, which was consistent with the combined analysis: bilateral subgroup (SMD =0.25, 95% CI: 0.12 to 0.37, P=0.0001), unilateral subgroup (SMD =0.70, 95% CI: 0.55 to 0.84, P=0.0001).Discussion: Operation time is one of the related factors of delirium after THA. The longer the operation time, the greater the possibility of delirium.