In a 226-Patient Trial, Filming Each TB Pill Beat a Health Worker's Visit at Getting Doses Seen
Story et al. (The Lancet, 2019) randomised 226 tuberculosis patients in England to film every dose or be watched in person. 70% vs 31% reached 80% of doses observed; clinical outcomes did not differ.
In this article9 sections
In a randomised trial of 226 tuberculosis patients in England, 70% of those who filmed themselves taking every dose reached the goal of having at least 80% of their scheduled doses observed over two months. Among patients visited in person by a health worker, 31% did (Story et al., The Lancet, 2019). The trial counted how often doses were seen. It found no significant difference in clinical results.
Consumer apps that ask for a short video after an alarm, DontSnooze among them, borrow the same idea at far lower stakes, which is a reason to look at the one place where the idea was tested properly, on people who had to take a pill daily for six months.
How the trial compared filming with visiting
Tuberculosis is treated with a long course of drugs, and missed doses allow the bacteria to survive. Directly observed therapy, or DOT, has a health worker or lay worker watch the patient take the dose. In this trial, in-person observers saw patients three to five times a week, and the remaining doses were self-administered. Among the 56 DOT patients who got going at all, 27 were visited at home, 20 attended a clinic and 9 were seen in the community.
The video arm ran differently. Patients were trained to “record and send videos of every dose ingested 7 days per week using a smartphone app.” Trained staff in a central London service watched the clips later through a password-protected website. Observation was asynchronous, so nobody had to be present when the dose was swallowed.
The trial ran across 22 clinics: 17 in London, three in Birmingham, one in Coventry and one in Leicester. Between 1 September 2014 and 1 October 2016, 548 patients were screened, 322 were ineligible and 226 were randomised, 112 to video and 114 to DOT. The primary outcome was “successful completion of 80% or more of scheduled treatment observations” in the two months after randomisation.
What the numbers say
| Video (n = 112) | In person (n = 114) | |
|---|---|---|
| Met the 80% goal | 78 (70%) | 35 (31%) |
| Observed at least one week | 101 (90%) | 56 (49%) |
| Scheduled observations completed, first two months | 79% (5,091 of 6,474) | 45% (1,774 of 3,922) |
| Scheduled observations completed, full follow-up of up to six months | 77% | 39% |
The adjusted odds ratio for the primary outcome was 5.48 (95% CI 3.10 to 9.68). That is an odds ratio, and the authors caution that such figures “should not be regarded as accurate estimates of relative risk”; the unadjusted relative risk was about 2.27.
A second look at the table shows where the gap came from. Of the 114 patients in the in-person arm, 58 had less than a week of observation, against 11 of 112 in the video arm. The authors also ran an analysis restricted to patients with at least one week of observation, and its counts (101 and 56) match the one-week-engagement row above. There, 78 of 101 video patients (77%) met the goal against 35 of 56 in-person patients (63%). The headline gap of 39 percentage points shrinks to about 15 once the patients who never got started are set aside. In a further sensitivity analysis that counted only fully observed videos, the groups were 67% and 63%, an odds ratio of 1.44 (p = 0.273), which is not significant. Most of the video arm’s advantage, by this arithmetic, was getting people into observation and keeping them there, and a smaller part was doing better once observation was under way.
What the trial could not show
The authors list their own limits plainly. Patients and observers could not be blinded to the arm. Roughly 7% of video clips in the first two months were corrupted by a software bug; the main analysis counted them as observed, and a sensitivity analysis gave similar results. The video arm was scheduled for seven days a week and the in-person arm for fewer, so the primary outcome asked more of the video arm, which the authors say may favour DOT. And the sentence that matters most for anyone tempted to treat a video as a measure of behaviour: “We could not distinguish between doses that were not observed and doses that were not taken.”
Clinical results were a wash. There were no significant differences in sputum culture at two months, treatment completion, loss to follow-up or hospital admissions, and the study was not powered to find them. Video patients reported more adverse events (368 events from 32 patients, against 184 from 15 in the in-person arm). Patients in the video arm were encouraged to report adverse events on the clips themselves, and the paper does not say whether that explains the difference.
On staff time, the video service spent 3.2 minutes per dose observed. Clinic-based DOT took 15 minutes and community-based DOT 56 minutes, travel included.
What carries over to a wake-up video
The trial supports a narrow claim: a recorded clip that a person reviews later is easier to keep up than a person who has to be somewhere at a set time, at least for people who have a charged smartphone. It does not show that being watched makes anyone more motivated. The in-person arm was handicapped by logistics, with visits to arrange, travel to make and appointments to miss, and the study cannot separate “someone is watching” from “watching has become easy”. That is a reading of the results, not something the authors tested.
For anyone asking a friend to witness a morning routine, the useful lesson is about the observer’s burden. A friend who must be awake at 6:30 to confirm something is a DOT visit. A clip waiting on their phone when they wake up is a video dose. The 7% corrupted clips are also a reminder that proof can fail for dull technical reasons, and that a missing clip says little about what the person did. The same limit shows up in the ranking of proof types in this blog’s piece on why video beats self-report, and it is a reason to treat a missing video as a prompt for a conversation rather than a verdict.
The setting also differs in a way no analogy repairs. Tuberculosis patients face a six-month course with an infectious disease at stake, and the observers were health services with a duty of care. Whether the same pattern holds for a person trying to stop snoozing is untested. Smaller trials of reminders on health behaviour, such as the NHS text-message trial on missed appointments, point in a compatible direction, though they test a different lever.
Frequently asked questions
Did video-observed therapy cure more tuberculosis patients than in-person observation?
The trial did not show that. It was not powered to detect differences in relapse or drug resistance, and patients with multidrug-resistant tuberculosis were excluded from the randomised comparison and followed in a separate non-randomised arm.
What equipment did patients in the video arm use?
The study supplied smartphones (Samsung Galaxy S3, S4 or Xcover3 models) and data plans free of charge. Patients who had no way to charge a smartphone were excluded, so the result describes people who could keep a phone running.
How much did each approach cost?
Over six months the authors estimated about £5,700 per patient for in-person observation five times a week and £3,420 for three times a week. Daily video observation came to £1,645 per patient, assuming a service managing 50 patients.
Who ran the trial and where was it published?
Alistair Story and Andrew Hayward, both of University College London, with colleagues. It appeared in The Lancet on 23 March 2019, volume 393, issue 10177, pages 1216 to 1224.