Table 1 Study characteristics
Intracranial aneurysm type and follow-upNeurosurgical treatment/endovascular treatment
Included trialsCohortStudy timeNumber of randomized/included patients (n)Patients allocated to this treatment (n)Male subjects (%)Mean or median age (years)Mean aneurysm size (mm)Aneurysm location in anterior circulation (%)Clipping/coilingHunt and Hess grades I and II (%)OutcomesFollow-up
Ruptured intracranial aneurysms RCTs (first author, year published )
 Molyneux, 20027ISAT*1994–2002*21431070/107337/3752/5292% ≤ 10 mm97 Anterior circulation for all patientsNAmRS*2 Months
 Spetzler, 201393BRAT*2003–2007472*239/23330/2953/547/773/7352/53mRS*At discharge, exact time since treatment not stated
 Vanninen, 199936Finnish study population1995–199711157/5240/5450/497/691/8863/59GOS*3 Months
Observational studies (first author, year published)
 Birski, 201468Single center, Poland2003–20088669/17NANANA100/10035/48GOS, mRS, mortalityAt discharge
 Brunken, 200942Single center, Germany, Hamburg-Altona1990–2004515370/1453850.7/53.7NA96/77H&H 1–3 (73/72)GOS, deathAt discharge
 Chalouhi, 201278Single center, USA, Philadelphia2004–201115160/9132/2952/543/370/5743/30GOSAt discharge
 Fukui, 200449Single center, Japan1997–2001180142/3838/4256/59NA99/5349/55GOSAt discharge
 Goddard, 200472Single center, UK, Nottingham1995–1999292212/8031/2654/54NA89/93NAModified GOS, mortalityAt discharge
 Hamada, 200450Multicentre, Japan, Kumamoto1996–200016341456/178NANANANANAGOS3 Months
 Hoh, 200482Single center, USA, Massachusetts1995–2003515413/7930/2254/588/1187/5846/32mRS, mortalityAt discharge
 Khandelwal, 200552Single center, Japan, Fuijita1997–2003450324/126NANA/> 70NA93/76Hunt and Kosnik grade I–II (32/27)GOSAt discharge
 Liao, 2013101Single center, Taiwan, Kaohsiung2008–200910044/5639/3257/58NA100/10064/66mRSAt discharge
 Liu, 201371Multicentre,Taiwan2001–2005642325/22933/4057/56≥5 mm 60/69*NA61/65mRS2 Months
 Mortimer, 201424Single center, Australia2005–201013566/6928/3655/57≤ 10 mm (79/83)92/75NAmRS 0–2, length of hospital stay, ventilator time3 Months
 Natarajan, 200890Seattle, USA2005–2006195105/87NANA>10 mm (18/21)87/8583/74Mortality, mRS, discharge destination3 Months
 Nieuwkamp, 200666Two centers, Netherlands, Utrecht and Portugal, Lisbon1990–20044734/13NA≥ 75/≥ 75NANA/NANA/NAGOS, mortalityAt discharge
 Park, 201437Single center, Korea2008–201310846/62NA70/72NA/NANA/NA20/30GOS, mortalityAt discharge
 Richling, 199526Single center, Austria1991–1995220137/8342/3753/50NANA47/49GOS2–4 Weeks
 Sekhar 201392Single center, USA, Seattle, Washington2005–20126324/39NA49/587/70/0Mean 3/3mRS, mortality3 Months
 Taha, 200654Single center, Japan, Kokura2001–20045325/28NANANANA60/54GOS3 Months
 Tenjin, 201156Single center, Japan, Kyoto2006–201011377/36NA59/725/6100/86H&H 1–3 (79/64)mRS2 Months
 Tokimura, 201157Multicentre, Japan1999–20092319/321/050.7/49.25<10 mm (100/75)Distal PICA63/50GOS, deathAt discharge
 Varelas, 200696Single center, USA2000–2004188135/4834/5453/51NA89/65Mean 3/3 Mortality, discharge destinationAt discharge
 Zaidat, 200998Buffalo, USA1999–2005216118/9828/2852/58NA86/7083/74Mortality19 Days/16 days
 Zhang, 201233Single center, China2005–2009198122/7627/3653/52NA95/9171/70GOSAt discharge
Database registry studies (first author, year published)
 Alawi, 201473Kids' inpatient database1998–2009272130/142NANANANANAMortality, discharge destinationAt discharge
 Brinjikji, 201377US Nationwide inpatient Sample2001–200988 93053 207/35 723NA% ≥65 years(19/25)NANANAClinical outcome, mortalityAt discharge
 O’Kelly, 201028Ontario administrative databases, Canada1995–200431202342/77835/3354/54>25 mm 5/190/90NAMortality, destination at discharge, readmission30 Days
 Walendy, 201448German Diagnosis-Related Group data2005–200910 9525595/535734/3453/53NA65/47NAMortalityAt discharge
Unruptured intracranial aneurysms
Short-term follow-up (<3 months)
Observational studies (first author, year published)
 Birski, 201468Single center, Poland2003–20087645/31NANANA100/1000/0GOS, mRs, mortalityAt discharge
 Brilstra, 200462Multicentre, Netherlands1997–20004932/1928/2150/51>10 mm 8/3297/630/0mRS, QoL3 Months (12 months not reported for clinical outcome)
 Brunken, 200942Single center, Germany, Hamburg-Altona1990–200413851/87NA51/51NA98/870/0GOS, mortalityAt discharge
 Dammann, 201443Single center, Germany, Essen2006–201010387/1634/3754/549/6100/1000/0GOSAt discharge
 Iwamuro, 200751Single center, Japan, Fukuoka2000–200513278/5430/13NA/64NA90/260/0mRS3 months
 Johnston, 200019UCSF hospital discharge database1990–200013068/7215/1853/575–25 mm (84/75)87/680/0mRSAt discharge
 Kim, 2010102Multicentre Korea2006–20071.696846/824NANANANA0/0Clinical outcome, mortality30 Days
 Park, 201438Single center, Korea, Suwon2008–20135112/39NANANANA0/0GOS, mortalityAt discharge
 Sekhar, 201392Single center, USA, Washington, Seattle2005–20123713/24NA57/6113/90/00/0mRS3 Months
 Song, 201560Single center, Korea, Seoul2008–20141124558/56632/2256/56> 10 mm 11/1699/870/0mRS1 Month
 Wiebers, 20035ISUIA, multicenter study1991–199823681917/45124/2252/54> 12 mm 21/4291/760/0mRSAt 30 days
Database registry studies (first author, year published)
 Alawi, 201473Kids’ inpatient database1998–200984870/77857/5014/11NANA0Death,discharge destinationAt discharge
 Barker, 200475US Nationwide inpatient Sample1996–200039193498/42124/2354/56NANA0Mortality, discharge destinationAt discharge
 Brinjikji, 201176US Nationwide inpatient Sample2001–200864 04329 918/34 125NA53/56NANA0Mortality, discharge to long-term facilityAt discharge
 Higashida, 200781Database of non-federal hospital with coverage of 58% of US population1998–200025351881/65425/3154/54NANA0Death,discharge destinationAt discharge
 Jalbert, 201584Medicare Provider and Analysis and Review Data, and the American Hospital Association's Annual Survey Database, USA2000–201012 2994357/794223/2171/74NANA0Mortality, discharge destination, complicationsAt discharge, 30 days mortality
 Johnston, 199985University Health System Consortium database1994–199726122357/25526/2651.9/54.5NANA0Mortaility destination dischargeAt 30 Days
 Johnston, 200186Office of Statewide Health Planning and Development of California database1990–199820691699/37027/2254/55.6NANA0Mortality, destination at dischargeAt discharge
 Lad, 201387Thomson Reuter's Market Scan database2000–200945041878/262623/2353/55NANA0MortalityAt discharge and 30 and 90 days
 McDonald, 201388The perspective database2006–201127601380/138026/2555/54NANA0Matched by propensity score; in-hospital mortality, discharge destinationAt discharge
 Zacharia, 201497New York Statewide Planning and Research Cooperative System, USA2005–20102692NANANANANA0Discharge destination,clinical outcomeAt discharge
Ruptured intracranial aneurysm
Intermediate term follow-up (3 months—1 year)
RCTs (first author, year published)
 Koivisto, 200094Finnish study population1995–199711157/5240/5450/497/691/8863/59GOS1 Year
 Li, 201229Single center, China2005–200919296/9667/7254/55NA90/8666/60mRS1 Year
 McDougall, 201289BRAT*2003–2007472*239/23330/2953/547/773/7352/53mRS1 Year
 Molyneux, 200522ISAT*1994–2002*21431070/107337/3752/5292% ≤ 10 mm97 Anterior circulation for all patientsNAmRS1 Year
Observational studies (first author, year published)
 Diaz, 201279Single center, USA, Houston2005–2010199/1058/5857/43< 10 mm (67/ 100)100/100NAmRS6 Months
 Goddard, 200472Single center, UK, Nottingham1995–1999292212/8031/2654/54NA98/91NAGOS, mortality4–8 Months
 Groden, 2001103Single center, Germany, Hamburg1993–19994121/2043/4053/54≥15 mm (14.3/35)100/1000/0GOS6 Months
 Güresir, 201144Single center, Germany, Frankfurt am Main1999–2009201163/38NANANA100/100Grade I–III 57/76mRS6 Months
 Helland, 2006104Single center, Norway1987–2004286203/8346/4251/55NA97/8456/51GOS6 Months
 Hui, 201183Two centers, USA, Cleveland, Ohio and Atlanta, Georgia1999–20096035/25NANANA100/10046/52mRS6 Months
 Koh, 201369Single center, Singapore2005–20095633/2346/3554/53NA94/78NAGOS6 Months
 Lasjaunias, 200540Single center, FranceNA135/760/508/9NA100/060/57Clinical outcomeUp to 4 years
 Liang, 200930Single center, China, Beijing1985–20087¾67/258/12>10 mm 67/50100/50100/50GOS, mortality1 Year
 Liu, 201371Multicentre,Taiwan2001–2005642361/28133/4057/56≥5 mm 60/69NA61/65mRS1 Year
 Lusseveld, 200264Two centers, Netherlands, Tilburg and Utrecht1983–19998844/4441/3444/47≥10 mm (64/48)Basilar tip onlyNAGOS4 Months
 Niskanen, 200435Single center, Finland, Koupio1997–2000171103/6843/4754/54>8 mm 21/18100/10073/71GOS12 Months
 Park, 201437Single center, Korea2002–201116585/80NA76/74NANANAmRS1 Year
 Phillips, 201125Single center, Australia, Melbourne1997–2007459291/168NANANANANAmRS6 Months
Premananda, 201261Single center, Malaysia, Kuala Lumpur2005–2009268204/64NANANA95/70NAmRS6 Months
 Proust, 200341 (8 patients unruptured included, data not presented separately)Single center, France1990–2000223186/37NA47/57≥10 mm (21/5)100/10034/27GOS6–12 Months
 Rabinstein, 200391Single center, USA, Minnesota1990–2000415339/7635/3853/56NA81/47NAGOS, mortality6 Months
 Ronne-Engström, 200970Single center, Sweden1997–2006997333/66431/3456/56NA100/NA54/52Mortality, GOS6 Months
 Sekhar, 201392Single center, USA, Seattle, Washington2005–20126324/39NA49/587/70Mean 3/3mRS1 Year
 Simon, 2007105Single center, China, Hong Kong1995–200116989/8037/4057/565/597/84NAGOS, mortality1 Year
 Steiger, 199947Single center, Germany, Munich1990–19934534/11NANANANANAClinical outcome,death6 Months
 Stiefel, 200895Single center, USA, Pennsylvania1995–2007128/425/406/4Mean (6/11)63/5038/25GOS, mortality1 Year
 Tahir, 200967Single center, Pakistan2004–20075531/2429/5845/38≤ 8 mm 90/7597/8881/75mRS6 Months
 Taki, 201155Multicentre, Japn2006–2007588264/270NANAMean (6/7)96/78NAmRS1 Year
 Yang, 200832Single center, China, BeijingNA54/1NANANA75/0NAGOS, mortality1 Year
Unruptured intracranial aneurysm
Intermediate term follow-up (3 months—1 year)
Observational studies (first author, year published)
 Bhatia, 201174Singel center, USA, Pittsburg, PA2002–2007208157/68*NA53/57NA72/840/0GOS, mortality, stroke6 Months
 Dammann, 201443Single center, Germany, Essen2006–201010387/1634/3754/549/6100/1000/0GOS, mortality1 Year
 Diaz, 201279Single center, USA, Houston, Texas2005–20106525/4016/3351/61<10 mm 80/ 78100/1000/0mRS6 Months
 Hui, 201183Two centers, USA, Cleveland, Ohio and Atlanta, Georgia1999–20092720/7NANANA100/1000/0mRS, mortality6 Months
 Jang, 201158Singel center, Korea, Seoul1997–20098156/25NA71/71NA100/NA0/0Overall morbidity and mortality1 Year
 Liang, 200930Single center, China, Beijing1985–200841/3100/672/8≥10 mm (100/100)100/330/0Clinical outcome, mortality1 Year
 Niskanen, 200534Single center, Finland1997–2000135105/5340/6053/52Mean (7/7)98/830/0GOS12 Months
 Pyysalo, 201339Single center, Finland1989–19999438/5647/3950/51Mean (11/9)100/980/0Mortality1 Year
 Seifert, 200846Single center, Germany, Frankfurt am Main1999–2007206126/8027/3344/49≥ 12 mm (7/10)96/780/0mRS, death3–6 Months
 Sekhar, 201392Single center, USA, Seattle, Washington2005–20123713/24NA57/6113/90/00/0mRS1 Year
 Song, 201560Single center, Korea, Seoul2008–20141124558/56632/2256/56> 10 mm 11/1699/870/0mRS6 Months
 Wiebers, 20035ISUIA, multicenter study, USA, Canada and Europe1991–199823681917/45124/2252/5410/1391/760/0mRS1 Year
Ruptured intracranial aneurysm
Long-term follow-up (>1 year)
Randomized controlled trials (first author, year published)
 Spetzler, 20159BRAT2003–2007472*239/23330/2953/547/773/7352/53mRS6 Years
 Molyneux, 20158ISAT1994–2002*21431070/107337/3752/5292% ≤ 10 mm97 Anterior circulation for all patientsNAmRS10 Years
Observational studies (first author, year published)
 Birski, 201468Single center, Poland2003–20088669/17NANANA100/10035/48GOS, mRS, mortality>4 Years
 Fukui, 200449Single center, Japan, Nagoya1997–2001180142/3838/4256/59NA99/5349/55GOS21–34 Months (mean)
 Kim, 200859Four hospitals, Korea, Seoul1999–20065730/27NANANAAnterior choroidal aneurysm onlyH-H III (90/74)mRS27–34 Months (mean)
 Klompenhouwer, 201163Single center, Netherlands, Maastricht2000–2008403173/23030/3053/54>15 mm 7/44/1769/56mRS, mortality34 Months (mean)
 Liao, 2013101Single center, Taiwan, Kaohsiung2008–200910044/5639/3257/58NA100/10064/66mRS19 Months
 Liu, 201371Multicentre,Taiwan2001–2005642361/28133/4057/56≥ 5 mm 60/69NA61/65mRS2 Years
 Lot, 199923Single center, France, Paris1992–199628777/210NANANANA78/69Clinical outcome, death17 Months (mean)
Carvi y Nievas, 201065Singel center, Germany, Frankfurt am Main HöchstNA2111/1027/5052/52NA100/10036/40GOS18 Months (mean)
 Suzuki, 201153Single center, Japan, Sagamihara1987–20096855/1342/4658/57NA100/10062/38 (HK)*GOS43 Months (mean)
Unruptured intracranial aneurysm
Long-term outcome follow-up (>1 year)
Observational studies (first author, year published)
 Birski, 201468Single center, Poland2003–20086336/27NANANANA0GOS, mRs, mortality52 Months (mean)
 Kim, 200859Multicentre, Korea1999–20061510/5NANANAAnterior choroidal aneurysm only0mRS27–34 Months (mean)
 Kunz, 201345Singel center, Germany2000–2010563363/20031/3752/529/1193/650GOS, mortality13 months (mean)
 Lot, 199923Single center, Australia1992–199610825/83NANANANA0GOS, mortality17 Months (mean)
 Pyysalo, 201339Single center, Finland1989–19999438/5647/3950/51Mean (11/9)100/980Mortality5–15 Years
 Raftopoulos, 200327Single center, Belgium1996–20017739/3830/2949/46≥10 mm (28.2/23.6)96.5/830GOS38– 44 Months (mean)
Database registry studies (first author, year published)
 Gonda, 201480California Office of Statewide Health Planning and Development (OSHPD) database1998–200525091565/94425/2555/58NANA0MortalityMedian follow-up 7 years
 Lad, 201387Thomson Reuter's MarketScan database2000–200945041878/262623/2353/55NANA0Mortality2 Years (mean)
  • BRAT, Barrow Ruptured Aneurysm Trial; GOS, Glasgow Outcome Scale; H&H, Hunt and Hess; HK, Hunt and Kosnik grade; ISAT, International Subarachnoid Aneurysm Trial; mRs, modified Rankin scale; NA, not applicable; PICA, posterior interior cerebellar artery; QoL, quality of life; RCT, randomized controlled trial.