Clinical Correlates of Mass Effect in Autosomal Dominant Polycystic Kidney Disease

Abstract

Mass effect from polycystic kidney and liver enlargement can result in significant clinical complications and symptoms in autosomal dominant polycystic kidney disease (ADPKD). In this single-center study, we examined the correlation of height-adjusted total liver volume (htTLV) and total kidney volume (htTKV) by CT imaging with hepatic complications (n = 461) and abdominal symptoms (n = 253) in patients with ADPKD. "Mass-effect" complications were assessed by review of medical records and abdominal symptoms, by a standardized research questionnaire. Overall, 91.8% of patients had 4 or more liver cysts on CT scans. Polycystic liver disease (PLD) was classified as none or mild (htTLV < 1,600 mL/m); moderate (1,600 ≤ htTLV <3,200 mL/m); and severe (htTLV ≥ 3,200 mL/m). The prevalence of moderate and severe PLD in our patient cohort was 11.7% (n = 54/461) and 4.8% (n = 22/461), respectively, with a female predominance in both the moderate (61.1%) and severe (95.5%) PLD groups. Pressure-related complications such as leg edema (20.4%), ascites (16.6%), and hernia (3.6%) were common, and patients with moderate to severe PLD exhibited a 6-fold increased risk (compared to no or mild PLD) for these complications in multivariate analysis. Similarly, abdominal symptoms including back pain (58.8%), flank pain (53.1%), abdominal fullness (46.5%), and dyspnea/chest-discomfort (44.3%) were very common, and patients with moderate to severe PLD exhibited a 5-fold increased risk for these symptoms. Moderate to severe PLD is a common and clinically important problem in ~16% of patients with ADPKD who may benefit from referral to specialized centers for further management.

Fig 1. Distribution of height-adjusted total liver volume (htTLV) according to age and gender.

(A) Box plot of median (and inter-quartile range) of htTLV by age decades. The median htTLV was higher in males of age <40 and females ≥70 years (*P < 0.05 for gender difference). The skewing of htTLV towards larger size is most noticeable in females across all strata above 40 years of age, (P value for Jonckheere–Terpstra test for trend <0.001). (B) A scatter plot of htTLV by age and gender. Moderate PLD is moderately enriched by females and severe PLD, extremely enriched by females.

Fig 2. Prevalence of abdominal symptoms and hepatic complications.

(A) The prevalence of hepatic complications of all subjects. (B) The prevalence of abdominal symptoms on a three-point scale. Back pain and flank pain were most prevalent. Abdominal fullness and early satiety were common among moderate to severe symptoms (point 2 or 3).

Fig 3. Likelihood (log odds) of having complications or two or more pressure-related symptoms according to htTLV and the correlation between htTLV and htTKV or htTLV + htTKV.

(A) Positive likelihood of having pressure-related complications at htTLV ≥2,100 mL/m. (B) Positive likelihood of having two or more pressure–related symptoms at htTLV ≥ 1,600 mL/m. Note that htTLV≥3,200 mL/m was indicated as the threshold for severe polycystic liver disease. (C) The proportion of subjects and ratio of male to female according to htTLV of 1,600 mL/m and htTKV of 1,000 mL/m. (D) Correlation between htTLV and htTLV + htTKV.