What was the aim of this review?
To find out if it is possible to affect sickness absence by changing the length of time a worker is allowed to take time off work because of illness without a physician's certificate. We found five studies.
Key messages
We are uncertain whether changing the length of time a worker is allowed to take time off work because of illness without a physician's certificate has any effect on sickness absence, as the included studies reported very different results, and the certainty of the evidence was low to very low.
What was studied in the review?
Sickness absence prevents a person from working and thus may reduce income and causes costs to employers. Usually employers require a physician to certify sickness absence. This may not be meaningful in cases of less severe illnesses that pass quickly with rest. Self-certification of sickness absence is already used at many workplaces for sickness absence periods lasting typically from one day up to two weeks. In this review, we evaluated how change in the length of the self-certification period affects the mean number of sickness absence days, number of sickness absence periods, and the amount of lost work time at workplaces.
Why is this topic important?
Sickness absence is costly to society and to employers. Employers may have to continue paying the sick employee’s salary. After the employer’s obligation to pay has ended, insurance covers sickness benefits. Changing the practice of sickness certification in short sickness absences is expected to change employees' attitudes and behaviour, co-operation and climate at the workplace, and diminish sickness absence. Self-certification makes more healthcare resources available for other purposes.
What are the main results of the review?
We found five studies conducted between 1969 and 2014. One study evaluated the effect of prolonging the self-certification period among all insured workers in a large city and a region in Sweden in 1988. Three studies evaluated the effect of prolonging the self-certification period for employees of a few municipalities in Norway. One study evaluated the effect of introducing self-certification in an organisation in the UK in 1969. The time participants in the intervention groups were allowed to be off work without a doctor's certificate ranged from three days to one year. The included studies measured the effects on the mean number of sickness absence days, the number of sickness absence periods, or on lost work time due to sickness absence periods. All studies compared the effect of the change with practice-as-usual.
Effects on duration of sickness absence periods
Extending self-certification from one week to two weeks increased the mean duration of sickness absence. Introducing self-certification for a maximum of three days reduced the mean duration of sickness absences lasting up to three days. Extending self-certification from one to three days up to a year did not change the duration of sickness absence.
Effects on number of sickness absence periods
Extending self-certification from one week to two weeks did not change the number of sickness absence periods. Introducing self-certification for a maximum of three days increased sickness absence periods lasting up to three days. Extending self-certification from three days to up to a year decreased sickness absence periods.
Effects on lost work time
Extending self-certification from one week to two weeks resulted in an inferred increase in lost work time. Extending self-certification (from zero days to three days and from three days to five days) increased the amount of work time lost due to sickness absence periods lasting up to three days. Extending self-certification from ≤ 3 days to ≤ 50 days and from ≤ 3 days to ≤ 365 days reduced lost work time due to sickness absence periods of 4 to 16 days and > 16 days.
Costs of sickness absence and physician certification
The costs of sickness absence benefits resulting from a longer period of self-certification may be about six times greater than the possible reduction in costs of fewer physician appointments.
How up-to-date is this review?
We searched for studies up to 14 June 2018.
There is low- to very low-certainty evidence of inconsistent effects of changing the period of self-certification on the duration or frequency of short-term sickness absence periods or the amount of work time lost due to sickness absence. Because the evidence is of low or very low certainty, more and better studies are needed.
From the societal and employers' perspectives, sickness absence has a large economic impact. Internationally, there is variation in sickness certification practices. However, in most countries a physician's certificate of illness or reduced work ability is needed at some point of sickness absence. In many countries, there is a time period of varying length called the 'self-certification period' at the beginning of sickness absence. During that time a worker is not obliged to provide his or her employer a medical certificate and it is usually enough that the employee notifies his or her supervisor when taken ill. Self-certification can be introduced at organisational, regional, or national level.
To evaluate the effects of introducing, abolishing, or changing the period of self-certification of sickness absence on: the total or average duration (number of sickness absence days) of short-term sickness absence periods; the frequency of short-term sickness absence periods; the associated costs (of sickness absence and (occupational) health care); and social climate, supervisor involvement, and workload or presenteeism (see Figure 1).
We conducted a systematic literature search to identify all potentially eligible published and unpublished studies. We adapted the search strategy developed for MEDLINE for use in the other electronic databases. We also searched for unpublished trials on ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP). We used Google Scholar for exploratory searches.
We considered randomised controlled trials (RCTs), controlled before-after (CBA) studies, and interrupted time-series (ITS) studies for inclusion. We included studies carried out with individual employees or insured workers. We also included studies in which participants were addressed at the aggregate level of organisations, companies, municipalities, healthcare settings, or general populations. We included studies evaluating the effects of introducing, abolishing, or changing the period of self-certification of sickness absence.
We conducted a systematic literature search up to 14 June 2018. We calculated missing data from other data reported by the authors. We intended to perform a random-effects meta-analysis, but the studies were too different to enable meta-analysis.
We screened 6091 records for inclusion. Five studies fulfilled our inclusion criteria: one is an RCT and four are CBA studies. One study from Sweden changed the period of self-certification in 1985 in two districts for all insured inhabitants. Three studies from Norway conducted between 2001 and 2014 changed the period of self-certification in municipalities for all or part of the workers. One study from 1969 introduced self-certification for all manual workers of an oil refinery in the UK.
Longer compared to shorter self-certification for reducing sickness absence in workers
Outcome: average duration of sickness absence periods
Extending the period of self-certification from one week to two weeks produced a higher mean duration of sickness absence periods: mean difference in change values between the intervention and control group (MDchange) was 0.67 days/period up to 29 days (95% confidence interval (95% CI) 0.55 to 0.79; 1 RCT; low-certainty evidence).
The introduction of self-certification for a maximum of three days produced a lower mean duration of sickness absence up to three days (MDchange −0.32 days/period, 95% CI −0.39 to −0.25; 1 CBA study; very low-certainty evidence). The authors of a different study reported that prolonging self-certification from ≤ 3 days to ≤ 365 days did not lead to a change, but they did not provide numerical data (very low-certainty evidence).
Outcome: number of sickness absence periods per worker
Extending the period of self-certification from one week to two weeks resulted in no difference in the number of sickness absence periods in one RCT, but the authors did not report numerical data (low-certainty evidence).
The introduction of self-certification for a maximum of three days produced a higher mean number of sickness absence periods lasting up to three days (MDchange 0.48 periods, 95% CI 0.33 to 0.63) in one CBA study (very low-certainty evidence).
Extending the period of self-certification from three days to up to a year decreased the number of periods in one CBA study, but the authors did not report data (very low-certainty evidence).
Outcome: average lost work time per 100 person-years
Extending the period of self-certification from one week to two weeks resulted in an inferred increase in lost work time in one RCT (very low-certainty evidence).
Extending the period of self-certification (introduction of self-certification for a maximum of three days (from zero to three days) and from three days to five days, respectively) resulted in more work time lost due to sickness absence periods lasting up to three days in two CBA studies that could not be pooled (MDchange 0.54 days/person-year, 95% CI 0.47 to 0.61; and MDchange 1.38 days/person-year, 95% CI 1.16 to 1.60; very low-certainty evidence).
Extending the period of self-certification from three days up to 50 days led to 0.65 days less lost work time in one CBA study, based on absence periods lasting between four and 16 days. Extending the period of self-certification from three days up to 365 days resulted in less work time lost due to sickness absence periods longer than 16 days (MDchange −2.84 days, 95% CI −3.35 to −2.33; 1 CBA study; very low-certainty evidence).
Outcome: costs of sickness absence and physician certification
One RCT reported that the higher costs of sickness absence benefits incurred by extending the period of self-certification far outweighed the possible reduction in costs of fewer physician appointments by almost six to one (low-certainty evidence).
In summary, we found very low-certainty evidence that introducing self-certification of sickness absence or prolonging the self-certification period has inconsistent effects on the mean number of sickness absence days, the number of sickness absence periods, and on lost work time due to sickness absence periods.