2 Minute Medicine Rewind March 7, 2016


Randomized trial of labor induction in women 35 years of age or older

Over the last 30 years, women in industrialized nations have been increasingly delaying childbirth. This has important implications in the obstetric management of these patients as the risk of perinatal death, gestational diabetes mellitus, placenta previa and placental abruption are higher among women age 35 years and older. Mothers of advanced age are also at an increased risk of preterm labour, bearing infants with macrosomia or low birth weight. Induction at or before the due date in these women may be beneficial in reducing the risk of perinatal death, however may increase the risk of cesarean delivery. In this randomized controlled trial, 619 primigravid women age 35 years or older were assigned to labor induction between 39 weeks 0 days and 39 weeks 6 days of gestation or expectant management to evaluate the relationship between labor induction and risk of cesarean delivery. This trial was not designed or powered to assess the effects of labour induction on stillbirth. Researchers found no significant between-group differences with respect to maternal and neonatal outcomes. Specifically, there was no difference in rates of cesarean delivery (p=0.92), assisted vaginal delivery (p=0.08), neonatal hypoxia-related complications (p=0.98), admission to NICU for >4 days (p=0.85) or clinical measurements (i.e. birth weight, Apgar scores). This study therefore shows that among women of advanced maternal age, induction of labor at 39 weeks gestation as compared with expectant management had no significant effect on the rate of cesarean section, and no adverse short-term effects on maternal or neonatal outcomes.

High-dose perioperative atorvastatin and acute kidney injury following cardiac surgery: A randomized clinical trial

Acute kidney injury (AKI) complicates recovery after cardiac surgery in up to 30% of patients, and is associated with an increased risk of postoperative arrhythmias, respiratory failure, systemic infection, myocardial infarction and death while in hospital. Statins affect several mechanisms underlying postoperative AKI, and therefore, may improve post-operative outcomes in cardiac surgery patients at risk of AKI. In this randomized controlled trial, 615 patients were randomized to receive either atorvastatin or placebo to determine whether perioperative atorvastatin treatment reduces AKI following cardiac surgery. The dose of atorvastatin was dependent on prior use of the medication. Patients naïve to statin treatment were randomized to receive 80 mg atorvastatin the day prior to surgery, 40 mg atorvastatin the morning of surgery, and 40 mg atorvastatin daily following surgery for the duration of hospitalization, or a matching placebo regimen. Patients already taking a statin, preoperatively, were randomized to receive the study drug only on days where they otherwise would not have been prescribed a statin under standard of care; previous studies have demonstrated that statin withdrawal may increase the risk of AKI. As such, these patients continued to take their pre-enrollment statin until the day of surgery and resumed taking the previously prescribed statin on postoperative day 2. On the day of surgery, patients were randomly assigned to receive 80 mg of atorvastatin at least 3 hours prior to surgery and 40 mg atorvastatin the day after surgery, or a matching placebo regimen. Researchers found that there was no significant difference in the incidence of AKI between groups (RR 1.06, 95% CI 0.78 to 1.46, p=0.75). Median serum creatinine concentrations in the postoperative period were also similar between groups (mean difference -0.01 mg/dL, 95% CI -0.06 to 0.04 mg/dL, p=0.89). However, in analyzing the effect of the study drug in patients naïve to statin treatment, the authors found that the median serum creatinine concentration in the postoperative period was significantly elevated in patients initiating statin treatment compared to the placebo-matched controls (mean difference 0.08 mg/dL, 95% CI 0.01 to 0.15 mg/dL, 0.007). Furthermore, the results of another subgroup analysis of patients with chronic kidney disease (CKD) naïve to statin treatment, showed that AKI occurred in a greater proportion of patients that received atorvastatin compared to placebo (RR 3.35, 95% CI 1.12 to 10.05, p=0.03). In this subgroup, postoperative serum creatinine concentrations increased by a median of 0.26 mg/dL within the first 48 postoperative hours in patients in the atorvastatin group compared to a decrease of 0.06 mg/dL in the placebo group (mean difference 0.28mg/dL, 95% CI 0.02 to 0.54mg/dL, p=0.04). This study therefore shows that among patients undergoing cardiac surgery, high-dose perioperative atorvastatin treatment does not reduce the overall risk of AKI. These results also do not support the initiation of statin therapy as part of preventing AKI following cardiac surgery.

Association of financial strain with symptom burden and quality of life for patients with lung or colorectal cancer

The treatment of cancer poses significant costs to patients, from diagnosis to survivorship or end-of-life care. For many patients, this is a source of financial hardship, which studies have shown is positively associated with medication non-adherence and delaying medical care. It is unclear, however, how financial strain influences outcomes such as symptom burden and quality of life (QOL). In this large prospective cohort study, 5343 patients with either recently diagnosed lung or colorectal cancer were followed up over 12 months to assess the relationship between patient-reported financial strain and QOL. Patients participating in the study were interviewed about their financial reserves, QOL and symptom burden at 4 months of diagnosis, and for survivors, at 12 months of diagnosis. Overall QOL was measured using the 12-item Short Form Healy Survey (SF-12) physical and mental health scales, as well as the 5-item EuroQol-5 Dimension scale (EQ-5D), which provides a global measure of health-related QOL. Pain was measured using the Brief Pain Inventory, and symptom burden was measured using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 symptom inventory. Researchers found that at 4 months of follow-up, patients with limited financial resources reported significantly increased pain. This was true for patients affected by lung (mean difference 5.03, 95% CI 3.29 to 7.22) and colorectal cancer (mean difference 3.45, 95% CI 1.25 to 5.66). These patients also reported greater symptom burden, with similar mean differences between the lung (mean difference 5.25, 95% CI 3.29 to 7.22) and colorectal disease groups (mean difference 5.31, 95% CI 3.58 to 7.04). The effect of financial strain was also reflected in the significantly poorer QOL reported by patients with few financial resources and either lung (mean difference 4.70, 95% CI 2.82 to 6.58) or colorectal cancer (mean difference 5.22, 95% CI 3.61 to 6.82). After 1 year of follow-up, these associations continued to persist, despite adjustment for stage, comorbidity, insurance, and other clinical attributes. This study therefore shows that patients with cancer and limited financial resources more likely to experience greater symptom burden and decreased QOL.

Guillain-Barré Syndrome outbreak associated with Zika virus infection in French Polynesia: a case-control study

Between October 2013 and April 2014, French Polynesia experienced the largest Zika virus outbreak ever reported at that time. During this period, a number of patients presented with Guillain-Barré syndrome (GBS), an autoimmune condition characterized by acute or subacute flaccid paralysis, suggesting a possible causal relationship. Other diseases such as West Nile, Japanese encephalitis, chikungunya and dengue have also been reported to sometimes cause GBS. In this case-control study, 42 patients diagnosed with GBS were evaluated and compared to unaffected controls to assess whether Zika infection with or without dengue concurrent or sequential infection could be a risk factor in the development of GBS. For this study, two control groups were formed, where the first was comprised of patients seeking care for non-febrile illness (n=98), reflecting the general population. The second control group was established to investigate the role of past dengue infection in developing GBS in patients affected by Zika. These patients had RT-PCR-confirmed Zika viral infection but did not develop any neurological complications. In all patients, blood samples and/or serology were used to determine whether patients were currently infected with Zika or dengue virus, or had been in the past. Researchers found that, in the GBS group, 74% of patients had been recently infected with Zika virus (presence of IgM against Zika virus), but not dengue. Interestingly, all GBS patients with anti-dengue IgM also had IgM against Zika virus, suggesting that the anti-dengue IgM response could have resulted from cross-reactivity. Compared to the first control group where 36% of patients had been infected at some point or another with Zika virus, 98% of patients in the GBS group had been infected (OR 59.7, 95% CI 10.4 to infinity, p<0.0001). A neutralizing response against Zika virus was also observed for all patients in the GBS group, compared to 56% of patients in the first control group (OR 34.1, 95% CI 5.8 to infinity, p<0.0001). Past dengue virus history did not differ significantly between patients with GBS and those in the two control groups, where the proportion of patients previously infected with dengue virus was in excess of 83% in all groups. This study therefore shows that a causal relationship between GBS and Zika virus infection may exist.

Validation of the instant blood pressure smartphone app

Mobile health technologies include a number of unregulated consumer smartphone apps. The Instant Blood Pressure (IBP) app estimates blood pressure (BP) using a technique by which the top edge of the smartphone is placed on the left side of the chest, while the user places their right index finger over the smartphone’s camera. While these apps have proven popular amongst consumers, validation studies have yet to be performed. In this prospective cohort study, BP was measured in 101 patients using the IBP app and validated automated sphygmomanometers (gold standard) to determine the accuracy and precision of the IBP app. Researchers found that the mean difference between IBP and the gold standard was 12.4 mmHg (SD 10.5 mmHg) for systolic BP and 10.1 mmHg (SD 8.1 mmHg) for diastolic BP. They also noted that IBP tended to underestimate higher BPs and overestimate lower BPs. The sensitivity and specificity of IBP for hypertensive BPs were 22% and 92%, respectively. This study therefore shows that the BP measurements using the IBP app are highly inaccurate and should be used by consumers with caution.

Image: PD

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