**Background:** Hip fractures are among the most damaging osteoporotic fractures in the elderly, leading to reduced quality of life, severe morbidity, and increased mortality. With global aging, the incidence is expected to rise. In Japan, the elderly population (≥65 years) reached 36.21 million (28.8% of the total) in 2020. The Niigata Prefecture Osteoporotic Hip Fracture Study has tracked incidence approximately every 5 years since 1985. Previous reports showed an increase from 1985 to 2010, followed by a decrease between 2010 and 2015, attributed partly to the widespread use of osteoporosis treatment. This 2020 survey aimed to determine whether the declining trend continued and to assess current prevention and treatment practices.
**Methods:** Registration forms were sent to all orthopedic clinics and hospitals in Niigata Prefecture. Data were collected on all residents diagnosed with osteoporotic hip fracture from January 1 to December 31, 2020. Osteoporotic fractures were defined as those caused by small external forces (e.g., falls from standing height or lower). Fractures were classified as femoral neck or trochanteric. Exclusions: patients <60 years, those with high-energy trauma, pathological fractures, periprosthetic fractures, and those living outside the prefecture. A total of 25 orthopedic clinics and 48 hospitals participated. In November 2020, Niigata Prefecture had 2,198,210 residents (1,066,494 male; 1,131,716 female), with 721,618 (32.8%) aged ≥65 years. Incidence rates were calculated per 100,000 person-years and age-adjusted to the 1985 Japanese population aged ≥60 years. Statistical analyses included the Mantel–Haenszel extended Chi-square test and joinpoint trend analysis. Patients were also surveyed on fracture location (indoor/outdoor), pre-injury osteoporosis treatment, surgical method, and preoperative waiting time.
**Key Results:** In 2020, 3,369 hip fractures were recorded (661 males, mean age 82.7 years; 2,708 females, mean age 86.4 years; male-to-female ratio 1:4.1). The overall incidence in those aged ≥60 years was 388.3 per 100,000 per year. Patients aged ≥65 years accounted for 98.0% of fractures; those ≥85 years, 63.0%; and those ≥90 years, 36.9%. Compared to 2015, the proportion of fractures in those ≥85 years rose from 56.6% to 63.0%, and in those ≥90 years from 29.1% to 36.9%. Age-specific incidence increased in males aged 75–79, 85–89, and ≥90 years, and in females aged 65–69 and ≥90 years, while declining in most other age groups. Indoor fractures were significantly higher in 2020 (indoor-to-outdoor ratio 4.8:1) compared to 2015 (4.1:1) (χ²=5.879, p<0.05). Of the 3,110 patients who underwent surgery (92.3%), 49.6% were operated on within 48 hours. The mean preoperative waiting time was 2.9 days. The most common reason for delay >48 hours was "holidays" (40.4%), followed by operating room/anesthesiology availability (23.0%), delayed consultation (20.1%), medical comorbidities (12.8%), and orthopedic department convenience (7.6%). COVID-19-related delays accounted for 1.9%. The proportion of patients taking anti-osteoporosis drugs prior to fracture increased from 7.6% in 2004 to 10.2% in 2010, 14.9% in 2015, and 17.3% in 2020. However, only 199 of 3,369 patients (approximately 6%) were taking bisphosphonates. Age-adjusted incidence (using the 1985 Japanese population structure) showed that for females, incidence was highest in 2010 and significantly lower in 2015 and 2020 (p<0.001). For males, incidence was also highest in 2010 and significantly lower in 2015 and 2020 (p<0.001), though the difference between 2020 and 1994 was not significant (p=0.633). Joinpoint trend analysis did not confirm 2010 as a definitive peak for the overall trend.
**Clinical Implications:** The study confirms that the decline in hip fracture incidence observed between 2010 and 2015 has not continued uniformly; instead, fractures are increasing among the very elderly (≥90 years), who represent a growing demographic. The rising use of anti-osteoporosis drugs (17.3% in 2020) may have contributed to the overall stabilization, but the low bisphosphonate uptake (≈6%) indicates substantial room for improvement. The authors emphasize the need to expand osteoporosis treatment coverage, particularly through Fracture Liaison Services (only six existed in Niigata Prefecture). The mean preoperative waiting time of 2.9 days, while better than the national average (4.1–4.8 days), still falls short of the recommended 48-hour target. Addressing delays due to holidays, operating room scheduling, and medical comorbidities through multidisciplinary approaches could improve outcomes. The significant shift toward indoor fractures in 2020 likely reflects COVID-19 lockdown and travel restrictions. Limitations include exclusion of patients <60 years and reliance on survey forms rather than administrative databases. Overall, the study underscores that while progress has been made, intensified efforts in osteoporosis pharmacotherapy and perioperative care are needed to counter the rising fracture burden in the oldest old.