**1. Introduction**

346 Chronic Kidney Disease

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Benign Prostate Hyperplasia (BPH) is a common disease in adult men and its incidence is age related. On the basis of clinical criteria, the Baltimore Longitudinal Study of Aging found that the prevalence of BPH is approximately 25% in men aged 40 to 49 years, 50% in men aged 50 to 59 years, and 80% in men aged 70 to 79 years (Arrighi, Metter et al. 1991).

BHP is theoretically the detection of prostatic hyperplasia, which is the benign proliferation of the stroma and epithelium, by histological study. However histological studies for all men are unfeasible in clinical practice, so BHP usually refers to the palpable enlargement of the prostate, which can be detected by clinical or ultrasonographic examination, or presence of urinary symptoms loosely defined as lower urinary tract symptoms (LUTS), which are usually classified as obstructive or irritative (Levy and Samraj 2007).

Chronic kidney disease (CKD) encompasses a spectrum of different pathophysiologic processes associated with abnormal kidney function, and a progressive decline in glomerular filtration rate (GFR). *Chronic renal failure* (CRF) applies to the process of continuing significant irreversible reduction in nephron number, *end-stage renal disease* (ESRD) represents a stage of CKD where the accumulation of toxins, fluid, and electrolytes normally excreted by the kidneys results in the *uremic syndrome*. This syndrome leads to death unless the toxins are removed by renal replacement therapy, using dialysis or kidney transplantation (Fauci 2007). The prevalence of CRF using the Modification of Diet in Renal Disease equation is 26% in adults who are 70 years and older. Men are at 67% greater risk for advanced chronic renal failure and at 44% greater risk for end stage renal disease than women (Rule, Lieber et al. 2005).

Despite the many possible causes of obstructive uropathy, in studies of elderly patients with acute renal failure, the most common cause among all patients was BPH (Kumar, Hill et al. 1973; Tseng and Stoller 2009). Kumar et al., showed in their studies that acute renal failure in patients with obstructive uropathy were due to BPH (38%), neurogenic bladder (19%), obstructive pyelonephritis (15%).

Attending to high prevalence of BPH in older men with CKD it is invaluable to take into consideration the relationship between these two clinical entities. However, despite the high prevalence of CKD and BPH in elderly men, there is limited knowledge on the association between these two conditions.

Benign Prostate Hyperplasia and Chronic Kidney Disease 349

consultations for BPH and urinary symptoms constitute the largest share of visits in our department and in urology departments worldwide. In 1989, there were approximately 1,3 million office visits to physician for BPH (Schappert 1993), and in 1992 approximately 170.000 prostatectomies were performed among inpatients in the United States (Xia, Roberts et al. 1999; Wei, Calhoun et al. 2008). Agency for Health Care Policy and Research Diagnostic and Treatment for BPH showed that from 22.5 million white men aged 50 to 79 years in the United States, in 1990, approximately 5.6 million needed medical consultation and treatment for BPH, demonstrating this disease is a prevalent health problem (Wei,

Although BPH is not a life-threatening condition, the impact of BPH on quality of life (QoL) can be significant and should not be underestimated (McVary 2006). According to the World Health Organization although the death rate attributable to BPH is negligible, the estimated DALY's (The sum of years of potential life lost due to premature mortality and the years of productive life lost due to disability) due to BHP is quite considerable. Most of the disability is probably due to severe clinical symptoms and/or late complications of BPH like CKD

Chronic kidney disease is a serious condition associated with premature mortality, decreased quality of life, and increased health-care expenditures. Untreated CKD can result

The 1999-2004 National Health and Nutrition Examination Survey (NHANES) determined that 16.8% of the U.S. population aged >20 years had CKD (according to 1999-2004 data), compared with 14.5% from the 1988-1994 NHANES, an increase of 15.9% based on crude estimates of prevalence (Saydah 2007) which reflects the increasing needs for health care

**3. The relationship between benign prostatic hyperplasia and chronic kidney**

Although the exact etiology of BPH is not known it seems (from recent studies and daily clinical practice) that the natural history and evolution of benign prostatic enlargement ends

Both diseases are extremely common among aging male, leading some to suggest that it is a

In his 1989 retrospective study of 19 patients who were admitted to renal dialysis units for end-stage renal disease caused by BPH, authors (Sacks, Aparicio et al. 1989) raised awareness of BPH as a cause for CKD and suggested a more adequate screening of renal function in men with untreated LUTS. More recently a cross-sectional survey in Spain of 2,000 randomly sampled men who were 50 years or older showed a 2.4% prevalence of self-reported renal failure related to a prostate condition (9% reported renal failure from any cause) (Hunter, Berra-Unamuno et al. 1996; Rule, Lieber et al. 2005). The main limitation of this study was that it relied on the self report of CKD, and no distinction between Acute Renal Failure (ARF) or CKD was made. Nonetheless it remains one largest studies that reveals a connection between CKD and BPH (Hunter, Berra-Unamuno et al. 1996). Another study (Hill, Philpott et al. 1993) showed that men presenting for prostate

in end-stage renal disease requiring dialysis or kidney transplantation.

**disease – A consequence of urinary outflow obstruction?**

natural concomitant of aging (Wu, Li et al. 2006).

up in urinary obstruction causing degradation of renal function over time.

Calhoun et al. 2008).

(Organization 2011).

policy for CKD.

The purpose of this chapter is to discuss the relationship between BPH and CKD, bearing in mind the epidemiology, pathophysiology, the clinical and imagiologic presentation of BPH and how it can contribute to CKD.


*Article* **Evaluating Total Electron Content (TEC) Detrending Techniques in Determining Ionospheric Disturbances during Lightning Events in A Low Latitude Region**

**Louis Osei-Poku 1, Long Tang 1,2, Wu Chen 1,3,\* and Chen Mingli 4**

**Abstract:** Total Electron Content (TEC) from Global Navigation Satellite Systems (GNSS) is used to ascertain the impact of space weather events on navigation and communication systems. TEC is detrended by several methods to show this impact. Information from the detrended TEC may or may not necessarily represent a geophysical parameter. In this study, two commonly used detrending methods, Savitzky–Golay filter and polynomial fitting, are evaluated during thunderstorm events in Hong Kong. A two-step approach of detection and distinguishing is introduced alongside linear correlation in order to determine the best detrending model. Savitzky–Golay filter on order six and with a time window length of 120 min performed the best in detecting lightning events, and had the highest moderate positive correlation of 0.4. That the best time frame was 120 min suggests that the observed disturbances could be travelling ionospheric disturbance (TID), with lightning as the potential source.

**Keywords:** TEC; detrending; Savitzky–Golay; polynomial; lightning


*Article* **Fatigue Resistance and Cracking Mechanism of Semi-Flexible Pavement Mixture**

**Shiqi Wang 1,\*, Huanyun Zhou 1, Xianhua Chen 1,\*, Minghui Gong 2,3, Jinxiang Hong 2,3 and Xincheng Shi 1**

**Abstract:** Semi-flexible pavement (SFP) is widely used in recent years because of its good rutting resistance, but it is easy to crack under traffic loads. A large number of studies are aimed at improving its crack resistance. However, the understanding of its fatigue resistance and fatiguecracking mechanism is limited. Therefore, the semi-circular bending (SCB) fatigue test is used to evaluate the fatigue resistance of the SFP mixture. SCB fatigue tests under different temperature values and stress ratio were used to characterize the fatigue life of the SFP mixture, and its laboratory fatigue prediction model was established. The distribution of various phases of the SFP mixture in the fracture surface was analyzed by digital image processing technology, and its fatigue cracking mechanism was analyzed. The results show that the SFP mixture has better fatigue resistance under low temperature and low stress ratio, while its fatigue resistance under other environmental and load conditions is worse than that of asphalt mixture. The main reason for the poor fatigue resistance of the SFP mixture is the poor deformation capacity and low strength of grouting materials. Furthermore, the performance difference between grouting material and the asphalt binder is large, which leads to the difference of fatigue cracking mechanism of the SFP mixture under different conditions. Under the fatigue load, the weak position of the SFP mixture at a low temperature is asphalt binder and its interface with other materials, while at medium and high temperatures, the weak position of the SFP mixture is inside the grouting material. The research provides a basis for the calculation of the service life of the SFP structure, provides a reference for the improvement direction of the SFP mixture composition and internal structure.

**Keywords:** semi-flexible pavement; fatigue resistance; cracking mechanism; fatigue prediction; fracture surface