Rates of sickness certification in European primary care: A systematic review

Figures & data

Figure 1.  Flow chart showing the results of the systematic search and selection of studies.

Table I.  Items used to assess the quality of studies.

Item	Assessment
1. What is the research question?	Is the research question clearly presented? Does the research question follow from the rational?
2. What is the study type?	Is the study type appropriate to the research question?
3. What are the outcome factors, and how are they measured?	Are all the relevant outcomes assessed? Is there measurement error? Is measurement error a source of bias?
4. What are the study factors, and how are they measured?	Is there measurement error? Is measurement error a source of bias?
5. What important confounders are considered?	Are potential confounders controlled for? Is confounding a potential source of bias?
6. What are the sampling frame and sampling method?	Is there selection bias? Does the way participants are selected threaten the external validity of the study?
7. Issues of internal validity	How many participants reached follow-up? Are control participants appropriate? Does this threaten the internal validity of the study?
8. Are statistical tests considered?	Are the tests appropriate to the data? Are power calculations and confidence intervals reported?
9. Are the results clinically/socially significant?	Was the sample size large enough to detect a clinically/socially significant result? Is the study inconclusive?
10. Is the study ethical?	Is ethical approval reported?
11. What conclusions did the authors reach about the study question?	Are the conclusions supported by the results?

Adapted from Darzins et al. [5].

Table II.  Results of quality assessment.

Quality criteria	1 Research question	2 Study type	3 Outcome measures	4 Other study measures	5 Confounders	6 Sampling	7 Internal validity	8 Statistical tests	9 Clinical/social significance	10 Ethical issues	11 Conclusions	Score
Author*
Eade et al. [11]	+	−	+	−	−	+	−	−	+	−	+	5
Tellnes et al. [6]	+	−	+	+	+	+	−	+	+	−	+	8
Tellnes et al. [3]	+	+	+	−	−	+	−	+	+	−	+	7
Englund et al. [7]	+	+	+	+	−	+	−	+	+	−	+	7
Soler [12]	+	+	+	−	−	+	−	+	+	−	+	7
Shiels et al. [13]	+	+	+	+	−	+	−	+	+	−	+	8
García-Díaz et al. [14]	+	+	+	+	+	+	−	+	+	−	+	9
Hensing et al. [8]	+	+	+	+	−	+	−	+	+	−	+	8
Norrmén et al. [9]	+	+	+	+	−	+	−	+	+	+	+	9
Ihlebaek et al. [10]	+	+	+	+	−	+	−	+	+	−	+	8
Bollag et al. [15]	+	+	+	+	+	+	−	−	+	−	+	8

*Arranged by publication date.

Table III.  Study characteristics.

Authors	Year of publication	Country	Population	Data source	Data collection period
Eade et al. [11]	1979	UK	All patients registered at one general practice in the UK	Consultation data – unclear on how this was obtained	Four 2-week periods in Feb, May, July, and Oct 1976
Tellnes & Bjerkedal [6]	1989	Norway	16–69-year-old employed persons in one county with an initial certificate	National Insurance Office of the county, 5042 certificates	4 weeks, 25 February to 24 March 1985
Tellnes et al. [3]	1989	Norway	16–69-year-old employed persons in one county with an initial certificate	National Insurance Office of the county, 5042 certificates	4 weeks, 25 February to 24 March 1985
Englund & Svärdsudd [7]	2000	Sweden	53 GPs in one country in Sweden	Audit/protocol completed by GP	Two-week period in March 1996
Soler [12]	2003	Malta	All 421 employees at five Maltese organizations	Employer family physician records	All certificates issued between 1997 and 1999
Shiels et al. [13]	2004	UK	All persons registered at any of nine GP practices, >50 000 employed persons	Carbon copies of sickness certificates issued to patients	Over a period of 12 months
García-Díaz et al. [14]	2006	Spain	All patients registered at one health centre	Health centre records	January 2000 until December 2002
Hensing et al. [8]	2006	Norway	All persons aged 16–66 who were entitled to sickness benefits in 1994, 1996, 1998, and 2000	Norwegian National Insurance Administration	Data were collected for a full year in 1994, 1996, 1998, and 2000
Norrmén et al. [9]	2006	Sweden	All persons aged 18–64 years registered with a GP in Örebro county	Questionnaire	1996
Ihlebaek et al. [10]	2007	Norway	All persons aged 16–67 who were working full or part time	Questionnaire survey of selected participants from a national survey	Over a period of 3 months in the spring of 1996 and spring of 2003
Bollag et al. [15]	2007	Switzerland	Physicians with primary care activity participating in the Swiss Sentinel Surveillance Network	Swiss Sentinel Surveillance Network	1 year, 1 Jan to 31 Dec 2005

Table IV.  Rates of certification.

Authors	Period when certification required	Number of sickness certificates issued	Rate of certification	Comparable rate of certification*	Other results reported
Eade et al. (1979) [11]	Not stated, but UK is >7 days	53 certificates issued to 288 rheumatic patients	0.54 per person per year Calculated from data presented	54 per 100 person years	• More men received certificates, but there were more men eligible for certification, as more women were reported as not working • There was a relationship between the degree of symptoms and certification • For BP patients occupation was also associated with certification
Tellnes & Bjerkedal (1989) [6]	>3 days	5042 (4858 people)	580 per 1000 employed persons per year	58 per 100 employed persons per year	• Highest incidence in 20–29-year-olds • Highest incidence in service/manufacturing municipalities
Tellnes et al. (1989) [3]	>3 days	5042 (2257 female, 2785 male)	580 per 1000 employed persons per year (595.8 females, 567.7 males)	58 per 100 employed persons per year	• GPs issued 81% of certificates, hospital drs 13%, private consultants 2%, occupational drs 2%, and others/unknown 2% • Most frequent groups were respiratory system and musculoskeletal/connective tissue diseases
Englund & Svärdsudd (2000) [16]	>7 days	68 certificates	Calculated as 68/301=22.6 per 100 patients	22.6 per 100 consultations	• Sick-listing cases constituted 8.8% of all consultations • Median length of sick leave was 14 days, and 25% of all sick listing was partial • Pain conditions were the most common reason for sick listing
Soler (2003) [12]	>1 day	3015 episodes of certification	239 per 100 person years (23.9 per year)	239 per 100 person years	• Average duration of sickness episode was 2.9 days • The three most common episodes were upper respiratory tract infections, sprains and strains and gastro-enteritis • Very few certificates were issue for depression and anxiety
Shiels et al. (2004) [13]	Not stated, but UK is >7 days	13 127 certificates issued to 6271 patients	Calculated as 2.1 per person per year	210 per 100 person years	• Mean duration of certification of 9.9 weeks/69 days • Almost 10% of patients had a certificate duration of >28 weeks
García-Díaz et al. (2006) [14]	Not stated	1714 certificates issued to 1146 employees	14.7 per 100 persons per year	14.7 per 100 person years	• Musculoskeletal conditions accounted for the majority of certificates • Mean number of days lost per worker was 99.7 • Multivariate analysis demonstrated that longer episodes of absence were associated with being female, older age, self-employed, or a home worker
Hensing et al. (2006) [8]	>4 days	Not reported	Cumulative incidence of certification with psychiatric diagnosis was 1.7% in 1994, 4.6% in 2000 in women	—	• The incidence of certification with psychiatric diagnosis was higher in women than men • The incidence of certification with psychiatric diagnosis was higher in middle age (40–49 years) than in other groups • The incidence of certification with psychiatric diagnosis increased in all regions of Norway
Norrmén et al. (2006) [9]	>7 days	152 certificates	Calculated as 152/642×100=23 per 100 patients	23 per 100 consultations	• Experienced physicians certify patients sick more often than less experienced physicians • Physicians working part time certify patients with infectious diseases sick more often than physicians working full time • Physicians trained in social insurance medicine certify patients with musculoskeletal problems sick more often than physicians who do not have such training
Ihlebaek et al. (2007) [10]	>4 days	174 564 (in first 6 months of 1996)	0.18 per person per year calculated by data presented	18 per 100 person years	• There was poor concordance between % change in health complaints and corresponding sickness absence • The prevalence of back pain complaints and back pain related sickness absence remained unchanged over 7 years • Tiredness was the single complaint with the largest change in sickness absence, with an increase of >350%
Bollag et al. (2007) [15]	>3 days	24 847 certificates from 162 physicians	GPs issued 4.3 certificates per 100 consultations Internists issued 3.6 certificates per 100 consultations	4.3 per 100 consultations	• Psychosocial and work-related cofactors were mentioned on 19% of certificates • Longer absence from work (>3 weeks) was associated with a higher proportion of psychosocial and work-related cofactors

*Re-calculated to rate per 100 (if not already reported) to enable comparisons.

Figure 2.  Recommendations for a minimum data set when collecting sickness certification data.

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