Ann Robinson’s research reviews—19 June 2020

Ann Robinson reviews the latest research from the top medical journals

Migraine with aura a risk factor for cardiovascular disease, but is it clinically significant?

This large cohort study of women aged over 45 years found that women with self reported migraine with aura had a higher incidence of major cardiovascular disease events than women without migraine or with migraine without aura. The association between migraine with aura and major cardiovascular disease was stronger than the association with obesity, similar to the association with high blood pressure and total cholesterol, and not as strong as the impact of smoking or diabetes. The precise mechanisms linking cardiovascular disease and migraine with aura are still not well understood, though cortical spreading depolarisation may be a shared pathway. The main problem with this otherwise interesting study is that migraine and the other vascular risk factors were self reported and only assessed at baseline even though the study had a mean follow-up of 22 years. In addition, details of treatment weren’t available (and may have affected rates of cardiovascular disease), and the cohort was solely women who had low rates of cardiovascular disease overall.

JAMA doi:10.1001/jama.2020.7172

Screening for depression: the long and short of it

The Patient Health Questionnaire depression module (PHQ-9) is a 9-item self administered screening tool to detect and assess severity of depression. PHQ-2 is a shortened pre-screening form that asks about depressed mood and inability to feel pleasure (anhedonia). In this meta-analysis of individual participant data from 44 studies, the combination of PHQ-2 and PHQ-9 did not improve sensitivity over using PHQ-9 alone and only minimally improved specificity.  On the plus side, the combination approach reduced the number of participants needing to do the full PHQ-9 by 57%, although using PHQ-2 alone resulted in lower sensitivity and specificity, depending on the cut-off value used. Pre-screening with PHQ-2 makes sense: whether screening populations for depression improves mental health outcomes, however, is still not clear.

JAMA doi:10.1001/jama.2020.6504

Rethinking low value tests

Covid-19 has put a temporary stop to “routine” or “low value” tests, and this Canadian population-based cohort study should give pause for thought before we resume some of them. The study found that low risk patients who had a chest x ray, electrocardiogram, or smear test as part of an annual health examination (AHE) had more (though not many more) specialist visits, tests, and procedures at three and six months, than others who didn’t. The absolute risk of serious outcomes (hospitalisations or death) was low among screened and unscreened patients. It’s possible that some tests were requested because of undocumented clinical concerns, that abnormal test results accounted for the increase in referrals, and that people who get screened are more likely to seek or need further care. On balance though, the study suggests that unnecessary tests beget more unnecessary tests. Now is the perfect time for a rethink.

JAMA Intern Med doi:10.1001/jamainternmed.2020.1611

Wuhan: source of a possible covid vaccine?

This first in-human, open label, non-randomised, phase 1 trial in Wuhan of a recombinant adenovirus type-5 (Ad5) vectored covid-19 vaccine found that it is well tolerated and immunogenic at 28 days after vaccination. Humoral responses peaked at day 28 post-vaccination and rapid specific T cell responses from day 14. The high dose vaccine was more immunogenic than the middle dose and low dose vaccines but also associated with more side effects such as fatigue and muscle pain. This is one of  many potential vaccines undergoing rapid development; its early promise warrants further investigation.

Lancet doi:10.1016/S0140-6736(20)31208-3

Thrombectomy for stroke—time for action?

Trials in high income countries have shown that mechanical thrombectomy for strokes with large vessel occlusion improves outcomes. This study looked at the safety and efficacy in the public health system in Brazil, a middle income country. Thrombectomy resulted in no or only minor neurological deficit in 35% in the thrombectomy and standard care (including intravenous alteplase) group, compared with 20% in the control group (standard care alone). This was a significant difference and meant that the trial was halted early. Asymptomatic intracranial haemorrhage occurred in 51% of the patients in the thrombectomy group and 24.5% of those in the control group; symptomatic intracranial haemorrhage occurred in 4.5% of the patients in each group. Change is slow. It took 15 years for intravenous thrombolysis (such as alteplase) to be approved for use in Brazil’s public health system. The authors hope that this study will prompt faster adoption of mechanical thrombectomy.

N Engl J Med doi:10.1056/NEJMoa2000120

Ann Robinson is an NHS GP and health writer and broadcaster