**1. Introduction**

430 Chronic Kidney Disease

Teles F, Machado FG, Ventura BH, Malheiros DM, Fujihara CK, Silva LF, and Zatz R. (2009).

Thybo NK, Stephens N, Cooper A, Aalkjaer C, Heagerty AM, and Mulvany MJ. (1995).

Turkay C, Yonem O, Arici S, Koyuncu A, and Kanbay M. (2008). Effect of angiotensin-

Unstated A. (2001). Effect of 3 years of antihypertensive therapy on renal structure in type 1

Unstated A. (2002). K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. *Am J Kidney Dis* 39:S1-266. Urushihara M, Kagami S, Kuhara T, Tamaki T, and Kuroda Y. (2002). Glomerular

Westermann D, Rutschow S, Jager S, Linderer A, Anker S, Riad A, Unger T, Schultheiss HP,

Woessner JF, Jr. (1991). Matrix metalloproteinases and their inhibitors in connective tissue

Zhang L, Edwards DG, and Berecek KH. (1996). Effects of early captopril treatment and its

role of angiotensin type 1 receptor antagonism. *Diabetes* 56:641-6.

untreated essential hypertension. *Hypertension* 25:474-81.

Disease in Type 1 Diabetes (ESPRIT). *Diabetes* 50:843-50.

glomerulonephritis. *Nephrol Dial Transplant* 17:1189-96.

remodeling. *Faseb J* 5:2145-54.

*Hypertens* 18:201-26.

*Kidney Int* 75:72-9.

53:789-93.

Regression of glomerular injury by losartan in experimental diabetic nephropathy.

Effect of antihypertensive treatment on small arteries of patients with previously

converting enzyme inhibition on experimental hepatic fibrogenesis. *Dig Dis Sci*

diabetic patients with albuminuria: the European Study for the Prevention of Renal

distribution and gelatinolytic activity of matrix metalloproteinases in human

Pauschinger M, and Tschope C. (2007). Contributions of inflammation and cardiac matrix metalloproteinase activity to cardiac failure in diabetic cardiomyopathy: the

removal on plasma angiotensin converting enzyme (ACE) activity and arginine vasopressin in hypertensive rats (SHR) and normotensive rats (WKY). *Clin Exp*  Progressive transformation of disease profiles in the world can be partially explained by the existence of chronic diseases, as they are responsible for a large part of the worldwide morbidity and mortality rates, thus becoming pandemics. One of the diseases recognized as a public health problem is chronic renal failure (CRF) because of the negative impact it has on the health and health-related quality of life (HRQOL) of its sufferers (Atkins, 2005a, 2005b).

The concept of HRQOL is still inaccurate because it has been approached from a variety of disciplines such as philosophy, economics, medicine, sociology, public health, politics, ethics, etc. (Cardona & Agudelo, 2005).

According to the World Health Organization (WHO), HRQOL is the "individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns." (WHO, 2002) This concept includes physical and psychological aspects as well as the degree of independence, social relationships, environment and spirituality (Cardona et al., 2003). The approximately four hundred instruments for measuring HRQOL (Cardona & Agudelo, 2005) can be grouped into four categories: the ones that measure HRQOL in terms of its global definition, the ones using component-oriented approaches, those which focus on one component, and the combinations of any of the above (Fleury & Lana Da Costa, 2004).

The relationship between HRQOL in CRF patients and the treatment after renal failure has been studied repeatedly (Amoedo et al., 2004; De Alvaro et al., 1997; García et al., 2003; Leanza et al., 2000; Pérez et al., 2007; Rebollo et al., 1999, 2000a, 2000b; Sanz et al., 2004). However, there are insufficient studies on the relationship between early progression of renal damage and well-being (National Kidney Foundation [NKF], 2007). The recommendations of the Institute of Medicine (IOM) Workshop "Assessing Health and health-related quality of life Outcomes in Dialysis" are recorded in the KDOQI guidelines and supported by scientific evidence. The IOM recommends assessing the aforementioned relationship with valid, reliable, and useful instruments such as the Medical Outcomes

Health-Related Quality of Life in Chronic Renal Predialysis

follow-up measurements was fixed at 0.5.

Schizophrenia patients (Leese et al., 2008).

used to ensure reliability.

Patients Exposed to a Prevention Program – Medellín, 2007-2008 433

A formula with repeated measurements proposed by Frison and Pocock in 1992 (Frison et al., 1992) was used to calculate the sample probabilistically. The criteria were: type 1 error: 0.05, type 2 error: 0.20 (Power: 80%), a difference of 10 in the average value of both groups, a standard deviation (SD) of 34 for both groups (the highest SD observed during the validation of the SF-36 domains (Lugo et al., 2006). The correlation between basal and

The minimal sample size for each group was 137. There was a total of 274 patients. The researchers anticipated that locating patients would be difficult due to high mobility. Therefore, an oversampling of 50% was performed, obtaining a final sample of 411 patients, of which only 293 could be contacted. The sample for the healthcare provider offering the RPP consisted of 148 patients, and the sample for the healthcare provider offering conventional

The SF-36 consists of eight domains that were calculated by transforming the ordinal scale of the form's items into the corresponding score from 0 to 100 (Lugo et al., 2006). This model has been used to dene two summary scores, namely: the physical health summary score (PCS1) and the mental health summary score (MCS1). Each of these two components includes four SF-36 dimensions as follows: PCS1 includes physical functioning (PF), rolephysical (RP), body pain (BP) and general health (GH); MCS1 includes: vitality (V), social functioning (SF), role-emotional (RE) and mental health (MH). Furthermore, summary scores for physical and mental health were calculated using the same method applied in a reproducibility study of the SF-36 summary scores in HRQOL assessments for

Physical functioning (PF) is measured by assessing the ability to perform different kinds of simple and strenuous activities. Role physical (RP) is measured based on how much patients can devote themselves to their jobs and other activities. Bodily pain (BP) is measured based on pain intensity and on how it hinders daily work. General Health (GH) refers to the patients' assessment of their own health. Vitality (V) is measured by assessing the perception of energy, exhaustion, or fatigue. Social functioning (SF) is measured by observing how much the patients' health problems affect their social activities. Role emotional (RE) is measured in terms of what activities the patients stop doing due to emotional problems. Mental health (MH) is measured by assessing how nervous, sad, calm, discouraged, or happy the patients feel. Change in health has a scale which is independent from the aforementioned domains and is used to assess the health state of patients. The current health state is compared with the one

Upon receiving the patient's informed consent, the SF-36 was administered by qualified medicine students. Also, its correct administration was verified and double data entry was

One year later the total number of patients surveyed with the SF-36 was 133 for the RPP and 130 for CT. For the second application of the SF-36, data analysis was carried out assigning zero to the domains of deceased patients and imputing the remaining missing values

After imputing the domains, summary scores were calculated and their distribution explored using the Kolmogorov-Smirnov test to verify the normality assumption. A comparison was made between the HRQOL values obtained in the two measurements for each group. For this

exhibited by the same individual one year prior to the measurement.

through multiple linear regression (Alisson, 2001).

treatment consisted of 145 patients. This guaranteed the expected representativeness.

Study 36-Item Short Form (SF-36). The version used in this study was adapted for the Colombian culture (Lugo et al., 2006).

To follow the WHO's recommendation (Tazeen, 2006), the Colombian Ministry of Social Protection proposed a CRF prevention and control program for Colombian healthcare providers (Martínez & Valencia, 2005). One of such institutions has been developing a renal protection program (RPP) since 2004. Besides patient uptake and follow-up, this program also assists patients in the early stages of the condition to prevent progression and renal damage, to delay the need for renal replacement therapies (RRT). The Renal Protection Program (RPP) is an interdisciplinary healthcare program. It is based on a protocol that establishes educational talks and regular medical appointments for conducting clinical examinations and laboratory tests. The program is geared toward CKD patients and welcomes them since the early stages of their condition. Likewise, the program actively searches for early-stage CKD patients and refers them to nephrologists. The professionals involved in this program are: general practitioners, internists, nutritionists, nurses, and nephrologists. Their degree of involvement varies depending on the patients' CKD stage. First, a follow-up is performed on the underlying condition. Afterwards, patients in the first and second stages of CKD are assigned to the program's first healthcare level, which offers medical appointments with internists and nutrition professionals once per year for stage 1 patients, and every semester for stage 2 patients. The second healthcare level of the program is for patients in stages 3 and 4, and offers medical appointments with internists, nephrologists, and nutritionists every three years for stage 3 patients and every two months for stage 4 patients.

In contrast, other Colombian healthcare providers offered conventional treatment (CT) in 2004. CT consists of providing healthcare through general medicine once the patients feel the need to request this service. Conventional treatment follows no healthcare guidelines, does not search for patients actively, and offers no laboratory tests or regular appointments.

This study compares changes in the HRQOL of two patient groups during the early stages of CRF (one group having been exposed to a RPP from 2007 to 2008). Its aim is to provide evidence of interventions that ease the burden this disease represents for patients, families and society.
