Tuberculosis

How the guideline was developed

The NICE guideline does not currently recommend VOT as there was limited relevant evidence available at the time of development.

DOT versus VOT study methods

The study authors report that their research was the first randomised controlled trial comparing the level of treatment observation for DOT and asynchronous VOT (where video clips are recorded by patient and forwarded for later viewing by a healthcare professional).

The NIHR study (work package 5) was a multicentre, analyst-blinded, randomised controlled superiority trial comparing the efficacy of asynchronous VOT with clinic-, home- or community-based DOT in supporting adherence in patients with active tuberculosis (across 22 clinics in England).

DOT was delivered by following the recommendations in the NICE guideline, which involved treatment observation 3 to 5 times per week, with any remaining daily doses self-administered. For VOT, patients were trained to record and send videos of every dose ingested 7 days per week using a smartphone app (smartphones with data were provided to patients free of charge). The smartphone app automatically sends encrypted, time/date-stamped videos to a secure server via mobile or wifi network.

The primary outcome of the study was greater than or equal to 80% of scheduled observations successfully completed during the first 2 months following randomisation. The main secondary outcome also considered the scheduled observations successfully completed in the 2 months following randomisation and throughout treatment, but as a proportion of scheduled observations on a continuous scale rather than dichotomous as per the primary outcome. Primary analysis was by intention to treat.

The NIHR study also completed an economic comparison of costs of VOT versus DOT (work package 6). The analysis from the perspective of the NHS, included DOT observations costs per week at 2015 to 2016 prices. VOT costs included fixed costs of infrastructure set up (including smartphone, video storage and system licence) and nurse analysis of videos.

For further information on the study methods see the NIHR report and Lancet publications.

NIHR study results

The study randomly assigned 226 eligible patients to VOT (n=112) or DOT (n=114). A total of 131 (58%) patients had social risk factors (history of homelessness, drug use, imprisonment, alcohol or mental health problems), with no significant differences at baseline between the allocated groups.

For the primary outcome, greater than or equal to 80% scheduled observations successfully completed during the first 2 months following randomisation:

For the main secondary outcome, proportion of scheduled observations (on a continuous scale) successfully completed in the 2 months following randomisation and throughout treatment:

The authors also note that VOT not only supports professional treatment observation but can also be more convenient for patients than in-person DOT.

Economic study

The NIHR study provides cost estimates based on various scenarios, for example: observation of a 6 month course of treatment with daily VOT cost £1,645 per patient (for a VOT service that covers 50 patients) compared to £5,700 for 5 observations per week for DOT. In a smaller VOT service which covers 25 patients VOT would cost £2,600 per patient.

The economic analysis from the NIHR study of VOT versus DOT identified VOT is cheaper than DOT if service capacity is not below a particular threshold, given the fixed costs of VOT. Although a threshold analysis was not provided, the available data indicates that a VOT service that covers 10 patients would have similar costs to a DOT service which provides 5 observations per week over 6 months (£5,500 for VOT versus £5,700 for DOT).

The report concludes that for settings with sufficient demand for tuberculosis treatment support, VOT is cheaper for the NHS than DOT and has superior outcomes, and therefore VOT dominates DOT.