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Table 1 Summary of review and participant characteristics

From: Comparative effectiveness and safety of pharmacological and non-pharmacological interventions for insomnia: an overview of reviews

CharacteristicSystematic reviews with meta-analysis (n = 35)Systematic reviews without meta-analysis (n = 29)
Review characteristics
 Year of publication [n (%)]
  1990–19991 (3)1 (3)
  2000–20095 (14)9 (31)
  2010–201829 (83)19 (66)
 Literature search date [n (%)]
  1990–19991 (3)2 (7)
  2000–20097 (20)7 (24)
  2010–201924 (69)16 (55)
  Not reported3 (9)4 (14)
 Literature search coverage [n (%)]
  From database inception8 (23)3 (10)
  > 50 years prior to search date2 (6)3 (10)
  30–49 years prior to search date4 (11)9 (31)
  10–29 years prior to search date1 (3)1 (3)
  Not reported20 (57)13 (45)
 Region of publication [n (%)]
  Asia15 (43)2 (7)
  Europe8 (23)6 (21)
  North America11 (31)19 (65)a
  Oceania1 (3)2 (7)
  Number of included primary studies [mean (range)]27 (3–139)8 (2–22)
 Included study designs [n (%)]b
  Randomized controlled trials33 (94)23 (79)
  Non-randomized controlled trials7 (24)
  Quasi-experimental1 (3)3 (10)
  Observational4 (14)
  Not reported2 (6)4 (14)
Population characteristics
 Overall sample size [mean (range)]c1861 (171–6303)566 (34–1794)
 Mean age [range (years)]d45–56.653.3c
 Proportion of female participants [range (%)]e35.6–74.2
 Patients with co-morbidities [n (%)]
  No co-morbidities12 (34)6 (21)
  Mix of patients with and without co-morbidities9 (26)9 (31)
  All patients with co-morbidities11 (31)9 (31)
  Not reported3 (9)5 (17)
 Types of co-morbidities [n (%)]b
  Mental health conditions (various)9 (26)11 (38)
  Cancer8 (23)6 (21)
  Conditions causing chronic pain5 (14)
  Chronic illness (unspecified)4 (11)2 (7)
  Other sleep disorders4 (11)
  Dementia3 (9)2 (7)
  Physical disability2 (6)1 (3)
Treatment comparisons [n (%)]b
(v inactive controls)
(v active controls)
Benzodiazepines
(flurazepam, temazepam, triazolam)
3 (9)
--
2 (7)
1 (3)
Non-benzodiazepine receptor agonists
(zolpidem, zopiclone)
4 (11)
--
5 (17)
3 (10)
Suvorexant3 (9)
--
1 (3)
--
Antidepressants
(doxepin, trazodone)
5 (14)
--
5 (17)
3 (10)
Antipsychotics
(quetiapine)
--
--
4 (14)
--
Melatonin8 (23)
--
4 (14)
--
Diphenhydramine1 (3)
--
2 (7)
--
Cognitive behavioral therapy (CBT)
(CBT, CBT + behavioral intervention, multi-component CBT)
20 (57)
3 (9)
8 (28)
3 (10)
Behavioral interventions
(relaxation, sleep restriction, multi-component behavioral)
4 (11)
1 (3)
7 (24)
--
Mindfulness-based interventions1 (3)
--
--
--
Combination therapies
(CBT + pharmacotherapy)
1 (3)
--
1 (3)
--
  1. aIncludes 17 SRs from the USA
  2. bSR + MAs or SRs can contribute to multiple categories, totals will not equal 100%
  3. cSample size was not reported in 11 SR + MAs and 8 SRs
  4. dMean age was only reported in 1 SR and 7 SR + MAs
  5. eThe percentage of female patients was only reported in 7 SR + MAs