Distribution of nephrologists and regional variation in the clinical severity of IgA nephropathy at biopsy diagnosis in Japan: A cross-sectional study

Yusuke Okabayashi, Nobuo Tsuboi, Hoichi Amano, Yoichi Miyazaki, Tetsuya Kawamura, Makoto Ogura, Ichiei Narita, Toshiharu Ninomiya, Hitoshi Yokoyama, Takashi Yokoo

研究成果: ジャーナルへの寄稿記事

抄録

Objectives The clinical severity of IgA nephropathy (IgAN) at the time of biopsy diagnosis differs significantly among cases. One possible determinant of any such difference is the time taken for referral from the primary care physician to a nephrologist, but the definitive cause remains unclear. This study examined the contribution of the number of nephrologists per regional population as a potential social factor influencing the clinical severity at diagnosis among patients with IgAN in Japan, which has an ethnically homogeneous population. Design A cross-sectional study. Setting and participants Patients were registered in the Japan Renal Biopsy Registry (J-RBR), a nationwide multicentre registry, and 6426 patients diagnosed with IgAN were analysed. The facilities registered to the J-RBR were divided into 10 regions and the clinical features of IgAN at biopsy diagnosis, including renal function and level of proteinuria, were examined. Main outcome measures Renal prognosis risk at the time of biopsy diagnosis defined by Kidney Disease Improving Global Outcomes guideline 2012. Results Among the regions, there were significant differences in the estimated glomerular filtration rate (67.5-91.4 mL/min/1.73 m 2), urinary protein excretion rate (0.93-1.93 g/day) and renal prognosis risk group distribution at diagnosis. The severity of all clinical parameters was inversely correlated with the number of nephrologists per regional population, which showed an up to 2.7-fold difference among regions. A generalised linear mixed model revealed that a low number of nephrologists per regional population were significantly associated with fulfilment of clinical criteria indicating a very-high-risk renal prognosis (β=-0.484, 95% CI -0.959 to -0.010). Conclusions Among Japanese patients with IgAN, significant regional differences were detected in clinical severity at the time of diagnosis. Social factors, such as an uneven distribution of nephrologists across regions, may influence the timing of biopsy and determine such differences.

元の言語英語
記事番号e024317
ジャーナルBMJ open
8
発行部数10
DOI
出版物ステータス出版済み - 1 1 2018

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Immunoglobulin A
Japan
Cross-Sectional Studies
Kidney
Biopsy
Registries
Population
Kidney Diseases
Primary Care Physicians
Glomerular Filtration Rate
Proteinuria
Nephrologists
Linear Models
Referral and Consultation
Outcome Assessment (Health Care)
Guidelines
Proteins

All Science Journal Classification (ASJC) codes

  • Medicine(all)

これを引用

Distribution of nephrologists and regional variation in the clinical severity of IgA nephropathy at biopsy diagnosis in Japan : A cross-sectional study. / Okabayashi, Yusuke; Tsuboi, Nobuo; Amano, Hoichi; Miyazaki, Yoichi; Kawamura, Tetsuya; Ogura, Makoto; Narita, Ichiei; Ninomiya, Toshiharu; Yokoyama, Hitoshi; Yokoo, Takashi.

:: BMJ open, 巻 8, 番号 10, e024317, 01.01.2018.

研究成果: ジャーナルへの寄稿記事

Okabayashi, Y, Tsuboi, N, Amano, H, Miyazaki, Y, Kawamura, T, Ogura, M, Narita, I, Ninomiya, T, Yokoyama, H & Yokoo, T 2018, 'Distribution of nephrologists and regional variation in the clinical severity of IgA nephropathy at biopsy diagnosis in Japan: A cross-sectional study', BMJ open, 巻. 8, 番号 10, e024317. https://doi.org/10.1136/bmjopen-2018-024317
Okabayashi, Yusuke ; Tsuboi, Nobuo ; Amano, Hoichi ; Miyazaki, Yoichi ; Kawamura, Tetsuya ; Ogura, Makoto ; Narita, Ichiei ; Ninomiya, Toshiharu ; Yokoyama, Hitoshi ; Yokoo, Takashi. / Distribution of nephrologists and regional variation in the clinical severity of IgA nephropathy at biopsy diagnosis in Japan : A cross-sectional study. :: BMJ open. 2018 ; 巻 8, 番号 10.
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abstract = "Objectives The clinical severity of IgA nephropathy (IgAN) at the time of biopsy diagnosis differs significantly among cases. One possible determinant of any such difference is the time taken for referral from the primary care physician to a nephrologist, but the definitive cause remains unclear. This study examined the contribution of the number of nephrologists per regional population as a potential social factor influencing the clinical severity at diagnosis among patients with IgAN in Japan, which has an ethnically homogeneous population. Design A cross-sectional study. Setting and participants Patients were registered in the Japan Renal Biopsy Registry (J-RBR), a nationwide multicentre registry, and 6426 patients diagnosed with IgAN were analysed. The facilities registered to the J-RBR were divided into 10 regions and the clinical features of IgAN at biopsy diagnosis, including renal function and level of proteinuria, were examined. Main outcome measures Renal prognosis risk at the time of biopsy diagnosis defined by Kidney Disease Improving Global Outcomes guideline 2012. Results Among the regions, there were significant differences in the estimated glomerular filtration rate (67.5-91.4 mL/min/1.73 m 2), urinary protein excretion rate (0.93-1.93 g/day) and renal prognosis risk group distribution at diagnosis. The severity of all clinical parameters was inversely correlated with the number of nephrologists per regional population, which showed an up to 2.7-fold difference among regions. A generalised linear mixed model revealed that a low number of nephrologists per regional population were significantly associated with fulfilment of clinical criteria indicating a very-high-risk renal prognosis (β=-0.484, 95{\%} CI -0.959 to -0.010). Conclusions Among Japanese patients with IgAN, significant regional differences were detected in clinical severity at the time of diagnosis. Social factors, such as an uneven distribution of nephrologists across regions, may influence the timing of biopsy and determine such differences.",
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T1 - Distribution of nephrologists and regional variation in the clinical severity of IgA nephropathy at biopsy diagnosis in Japan

T2 - A cross-sectional study

AU - Okabayashi, Yusuke

AU - Tsuboi, Nobuo

AU - Amano, Hoichi

AU - Miyazaki, Yoichi

AU - Kawamura, Tetsuya

AU - Ogura, Makoto

AU - Narita, Ichiei

AU - Ninomiya, Toshiharu

AU - Yokoyama, Hitoshi

AU - Yokoo, Takashi

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Objectives The clinical severity of IgA nephropathy (IgAN) at the time of biopsy diagnosis differs significantly among cases. One possible determinant of any such difference is the time taken for referral from the primary care physician to a nephrologist, but the definitive cause remains unclear. This study examined the contribution of the number of nephrologists per regional population as a potential social factor influencing the clinical severity at diagnosis among patients with IgAN in Japan, which has an ethnically homogeneous population. Design A cross-sectional study. Setting and participants Patients were registered in the Japan Renal Biopsy Registry (J-RBR), a nationwide multicentre registry, and 6426 patients diagnosed with IgAN were analysed. The facilities registered to the J-RBR were divided into 10 regions and the clinical features of IgAN at biopsy diagnosis, including renal function and level of proteinuria, were examined. Main outcome measures Renal prognosis risk at the time of biopsy diagnosis defined by Kidney Disease Improving Global Outcomes guideline 2012. Results Among the regions, there were significant differences in the estimated glomerular filtration rate (67.5-91.4 mL/min/1.73 m 2), urinary protein excretion rate (0.93-1.93 g/day) and renal prognosis risk group distribution at diagnosis. The severity of all clinical parameters was inversely correlated with the number of nephrologists per regional population, which showed an up to 2.7-fold difference among regions. A generalised linear mixed model revealed that a low number of nephrologists per regional population were significantly associated with fulfilment of clinical criteria indicating a very-high-risk renal prognosis (β=-0.484, 95% CI -0.959 to -0.010). Conclusions Among Japanese patients with IgAN, significant regional differences were detected in clinical severity at the time of diagnosis. Social factors, such as an uneven distribution of nephrologists across regions, may influence the timing of biopsy and determine such differences.

AB - Objectives The clinical severity of IgA nephropathy (IgAN) at the time of biopsy diagnosis differs significantly among cases. One possible determinant of any such difference is the time taken for referral from the primary care physician to a nephrologist, but the definitive cause remains unclear. This study examined the contribution of the number of nephrologists per regional population as a potential social factor influencing the clinical severity at diagnosis among patients with IgAN in Japan, which has an ethnically homogeneous population. Design A cross-sectional study. Setting and participants Patients were registered in the Japan Renal Biopsy Registry (J-RBR), a nationwide multicentre registry, and 6426 patients diagnosed with IgAN were analysed. The facilities registered to the J-RBR were divided into 10 regions and the clinical features of IgAN at biopsy diagnosis, including renal function and level of proteinuria, were examined. Main outcome measures Renal prognosis risk at the time of biopsy diagnosis defined by Kidney Disease Improving Global Outcomes guideline 2012. Results Among the regions, there were significant differences in the estimated glomerular filtration rate (67.5-91.4 mL/min/1.73 m 2), urinary protein excretion rate (0.93-1.93 g/day) and renal prognosis risk group distribution at diagnosis. The severity of all clinical parameters was inversely correlated with the number of nephrologists per regional population, which showed an up to 2.7-fold difference among regions. A generalised linear mixed model revealed that a low number of nephrologists per regional population were significantly associated with fulfilment of clinical criteria indicating a very-high-risk renal prognosis (β=-0.484, 95% CI -0.959 to -0.010). Conclusions Among Japanese patients with IgAN, significant regional differences were detected in clinical severity at the time of diagnosis. Social factors, such as an uneven distribution of nephrologists across regions, may influence the timing of biopsy and determine such differences.

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