Table 1.

Summary of Studies of Group A.

Reference	Study design	Study intention	Location	Participants	Age, mean (SD)	Exclusion and deaths	Follow-up time	Time point of factors measured	Time frame observed for second fracture to occur	n, percentage/incidence of second HF	Interval between first and second HF
Chapurlat et al11	Population-based prospective cohort study (Study of Osteoporotic Fracture [SOF])	“Examine incidence of and risk factors for a second HF in elderly women”	4 clinical centers in Portland, Oregon, Minneapolis, Minnesota, Baltimore, Maryland, and Pennsylvania, USA	SOF: non-black women ≥65 years, 1986-1988 = baseline, 632 patients with HF for analysis	Baseline 1 HF group: 75 ± 6, baseline 2 HF group: 75 ± 5	Exclusion: severe trauma, unable to walk without assistance, bilateral hip replacement, previous HF, deaths including ipsilateral HF	3.7 years (mean)	Before first HF (1986-1988)	0-6.8 years	n = 53/632, incidence 0.023/py	2.3 yr (mean), 6.8 years maximum
Berry et al10	Population-based prospective follow-up cohort study (Framingham Heart Study)	“timing, incidence, risk factors, and mortality associated with second HF”	Framingham, Massachusetts	Framingham Heart Study: 5209 patients. 28-62 years in 1948, 481 first HF patient. April 1952 to December 2003: 178 participants in final model	Baseline 1 HF group: 80.3 ±9.5, baseline 2 HF group: 77.2 ± 10.2	Exclusion: periprosthetic deaths: 15.9% in 1 year, 45.4% within 5yrs	4.2 years (IQR, 1.4-8.9) until 2003/second HF/death	Closest to and preceding first HF	0-52 years	n = 15/89 (analysis) 14.8%, 2.3/100 py, 2.5% at 1 year, 5.7% at 3 years, 8.2% at 5 years, cumulative incidence for second HF/death (accounting for variable length of follow-up, competing risk of death): 0.5 years 1.0/11.9, 1 year 2.5/15.9, 2 years 4.2/24.8, 3 years 5.7/33.6, 5 years 8.2/45.4, 10 years 12.2/72.4	4.2 years (median), range: 1 month to 33.3 years
Mitani et al14	Retrospective case record study	“Elucidate the risk factors for second HF”	Shimizu Hospital, Tottori Prefecture, Japan	400 HF patients, 384 for analysis, index HF January 2001 to December 2007	83.1 ± 9.0 (range: 51-102)	Exclusion: pathological HF, high-impact trauma, death within 1 year (n = 11), <50 years (n = 5),	3.0 ± 1.4 years (mean)	First HF	0-7 years	n = 49/384, overall incidence of 0.043/py	21 months (median), 23.5 ± 13.7 (mean), 40.8% 1 year, 67.3% 2 years, 85.7% 3 years
Yamanashi et al17	Prospective follow-up cohort study	“clarify the risk factors for a second HF in patients who had had a previous HF”	4 hospitals, Japan	820 HF patients ≥ 65 years, 714 for analysis (1579.5 py), inclusion: January 1996 to December1999	First HF: 80.7 ± 7.6 years (range 65-99 years)	Exclusion: (106) pathological fracture, high-energy trauma	2.4 ± 1.4 yr (mean) until September 2001/second HF/death	First HF	23-71 months	45/714, incidence 0.029/py, annual incidence: first year 0.038/py, during the second year 0.028/py, during 3rd yr 0.018/py	44% in 8 months
Holt et al12	Prospective national multicentric audit Scottish Hip Fracture Audit	“Incidence, epidemiology, and outcomes of sequential HF”	All 22 orthopedic hospitals, Scotland, United Kingdom	28 392 HF patients > 50 years January 1998 to December 2005, 20 267 patients for analysis, 13 874 1-year surviving patients for analysis	2 HF group: 82, 1 HF group: 80	Exclusion: 3963 within last 6 months of data collection, not matched to database (214), simultaneous HF (35), ipsilateral HF, death within 6 months of first HF, data not available at 12 months, death: 32% by 12 months (6393)	3.9 years, maximum 8 years	First HF	6-12 months for analysis	n = 473 (2.3%) of 20 267, n = 350 (2.5%) of surviving patients/13 874	NG
Lönnroos et al13	Hospital register and medical records review (with prospective and retrospective inclusion part)	“Review HF to determine which were primary vs secondary, determine what percent of patients with primary HF have a second HF within 2 years, describe characteristics of patients with 2 incident HF including medication use”	27 municipalities in Central Finland Health Care District Central Finland Hospital, Finland	Prospective inclusion (first HF 2002-2003: 501 first HF patients ≥60 years), follow-up until December 2005, prospective and retrospective inclusion: 573 HF patients in 2002-2003 (41 with previous HF)	Prospective part: baseline 1 HF group: 81 (8), baseline 2 HF group: 80 (7), retrospective part: first HF: 78 (49-92), second HF: 81 (49-99)	Deaths: 230/501 without second HF	25.5 months (median, range: 0.03-47.9) until 2005	First HF	2-4 years/retrospective	Prospective inclusion: n = 34/501 (6.8%), retrospective + prospective: n = 75/573 (41 with previous HF), overall incidence 0.036 (CI: 0.025-0.051)/py, cumulative incidence, 1 year 5.8% (3.30-7.78), 2 years 8.11% (5.73-11.43)	Retrospective inclusion: range 0.03-14.0 years, prospective inclusion: 2-4 year
Wolinsky and Fitzgerald16	Prospective follow-up cohort study, Longitudinal Study on Aging (follow-up on the Supplement on Aging 1984 National Health Interview Survey)	“Assess the risk of subsequent HF”	United States	Start 1984: 7527 patients ≥ 70 years, 368 HF patients, 1984-1991, 27 second HF patients for analysis	79.7	Of 51 double billings: exclusion: 3 duplicates, 14 transfers, 7 rehospitalizations	1984-1991, mean follow-up to death: 674 days, mean follow-up to censoring: 1132days	First HF	0-8 years	27/368 (7.3%), 1/33.8py	613days (mean)
Ryg et al1	Nationwide population-based historical cohort	“Studying incidence of second HF, ensuing mortality, possible impact of comorbidity”	All Danish hospitals, Denmark	169 145 HF patients, January 1977 to December 2001	Baseline 77.0 ± 13.0	Exclusion: patients referred from outpatient clinics, still in hospital after index HF, deaths: 121 953 (72.1%)	3.8 years (median, 0-25 years), 1 041 177 py, first and second HF 1977-2001	First HF	0-25 years	27 834/169 145, overall incidence: 39/1000 py, cumulative incidence: 9% after 1 year	NG
Angthong et al8	Medical records evaluation	“evaluate which of the predisposing risk factors for first HF would continue to be effective for the development of the second HF in the elderly”	1 hospital, Bangkok, Thailand	125 HF patients ≥ 55 years, inclusion: index HF January 2000 to September 2008 (first and second—contralateral—HF)	NG	Exclusion: metabolic bone disease, renal osteodystrophy, ipsilateral primary and secondary tumor lesion, simultaneous HF, bisphosphonate, calcitonin, estrogen treatment, pathological, high-energy trauma	January 2000 to September 2008	First HF	0-8.75 years	28/125	≤12 months n = 6 (21.4%), >12 months n = 22 (78.6%)
Baudoin et al9	Prospective study	“Evaluate burden of HF, whether they occurred at home or in a community, in terms of HF incidence and mortality and postoperative complications 2 years after HF”	34 surgical units, Picardie, France	1512 HF patients ≥20 years in December 1992 to December 1994, analysis: 1459; 567 for analysis	Community women 85 (7.2), community men 80.5 (10.2), home women 80.3 (9.2), home men 75.4 (11.0)	Exclusion: metastatic or myelomatous fracture, periprosthetic fracture for analysis: <50 years, deaths (at 2-year follow-up): 394 women, 173 men, 87% of surviving patients interviewed at 24 months	2 years until December 1994	First HF	24 months	n = 52, crude incidence 2.94/100 py	NG
Omsland et al15	Retrospective population-based database review	“Examine cumulative incidences of second HF by sex, age, and time after first HF”	All 48 hospitals/health trusts, Norway	81 867 HF patients ≥50 years, January 1999 to December 2008	NG	Exclusion: patients with previous HF between 1994 and 1998	1999-2008	First HF	0-9 years	n = 7943/81 867, crude incidence women 379/10 000 py (CI: 370-389), men 333/10 000 py (CI: 318-349)	Women: 1.5 years (0.5-3.2), men: 1.2 (0.4-2.7); median (IQR)

Abbreviations: CI, confidence interval; HF, hip fracture; IQR, interquartile range; NG, not given; py, patient-years; SD, standard deviation.