António Lopes | Escola Superior de Educação de Coimbra (original) (raw)

Papers by António Lopes

Research paper thumbnail of Depression as a predictor of mortality and hospitalization among hemodialysis patients in the United States and Europe

Kidney International, 2002

In recent decades, important advances have been made hemodialysis patients in the United States a... more In recent decades, important advances have been made hemodialysis patients in the United States and Europe.

Research paper thumbnail of Health-related quality of life as a predictor of mortality and hospitalization: The Dialysis Outcomes and Practice Patterns Study (DOPPS

Kidney International, 2003

Research paper thumbnail of Screening for depression in hemodialysis patients: Associations with diagnosis, treatment, and outcomes in the DOPPS

Kidney International, 2004

Background. Depressive symptoms and depression are the most frequent psychologic problems reporte... more Background. Depressive symptoms and depression are the most frequent psychologic problems reported by hemodialysis patients. We assessed the prevalence of depressive symptoms and physician-diagnosed depression, their variations by country, and associations with treatment by antidepressants among hemodialysis patients. We also assessed whether depressive symptoms were independently associated with mortality, hospitalization, and dialysis withdrawal.

Research paper thumbnail of Health-related quality of life in the Dialysis Outcomes and Practice Patterns Study (DOPPS

American Journal of Kidney Diseases, 2004

Background: Health-related quality of life (HRQOL), a validated system of measuring patients' phy... more Background: Health-related quality of life (HRQOL), a validated system of measuring patients' physical, mental, and social well-being, can be of particular use in populations with chronic conditions, such as end-stage renal disease (ESRD). Methods: The Dialysis Outcomes and Practice Patterns Study (DOPPS) has used the Kidney Disease Quality of Life Short Form (KDQOL-SF) to measure ESRD patients' self-assessment of functioning and well-being, as measured by 3 component scores: physical component summary (PCS, 4 subscales), mental component summary (4 subscales), and kidney disease component summary (11 subscales). Several DOPPS studies examined HRQOL's associations with mortality and hospitalization by country, ethnicity (United States only)

Research paper thumbnail of Health-related quality of life and associated outcomes among hemodialysis patients of different ethnicities in the United States: The Dialysis Outcomes and Practice Patterns Study (DOPPS

American Journal of Kidney Diseases, 2003

Background: In the United States, an association between mortality risk and ethnicity has been ob... more Background: In the United States, an association between mortality risk and ethnicity has been observed among hemodialysis patients. This study was developed to assess whether health-related quality of life (HRQOL) scores also vary among patients of different ethnic backgrounds. Associations between HRQOL and adverse dialysis outcomes (ie, death and hospitalization) also were assessed for all patients and by ethnicity. Methods: Data are from the Dialysis Outcomes and Practice Patterns Study for 6,151 hemodialysis patients treated in 148 US dialysis facilities who filled out the Kidney Disease Quality of Life Short Form. We determined scores for three components of HRQOL: Physical Component Summary (PCS), Mental Component Summary (MCS), and Kidney Disease Component Summary (KDCS). Patients were classified by ethnicity as Hispanic and five non-Hispanic categories: white, African American, Asian, Native American, and other. Multiple linear regression models were used to estimate differences in HRQOL scores among ethnic groups, using whites as the referent category. Cox regression models were used for associations between HRQOL and outcomes. Regression models were adjusted for sociodemographic variables, delivered dialysis dose (equilibrated Kt/V), body mass index, years on dialysis therapy, and several laboratory/comorbidity variables. Results: Compared with whites, African Americans showed higher HRQOL scores for all three components (MCS, PCS, and KDCS). Asians had higher adjusted PCS scores than whites, but did not differ for MCS or KDCS scores. Compared with whites, Hispanic patients had significantly higher PCS scores and lower MCS and KDCS scores. Native Americans showed significantly lower adjusted MCS scores than whites. The three major components of HRQOL were significantly associated with death and hospitalization for the entire pooled population, independent of ethnicity. Conclusion: The data indicate important differences in HRQOL among patients of different ethnic groups in the United States. Furthermore, HRQOL scores predict death and hospitalization among these patients. Am J Kidney Dis 41:605-615.

Research paper thumbnail of The low birth weight hypothesis as a plausible explanation for the black/white differences in hypertension, non-insulin-dependent diabetes, and end-stage renal disease

American Journal of Kidney Diseases, 1995

It is well known that black Americans have a higher risk for low birth weight (LBW) than white Am... more It is well known that black Americans have a higher risk for low birth weight (LBW) than white Americans. In addition, blacks are at a higher risk for hypertension (HT), non-insulin dependent diabetes mellitus (NIDDM), and end-stage renal disease (ESRD), particularly ESRD attributed to HT (ESRD-HT) and NIDDM (ESRD-NIDDM). It has been shown that LBW is associated with postpartum anatomic and functional alterations in the kidney and pancreas as well as with progressive renal damage in animals and increased risk for HT and NIDDM during adulthood in humans. Based on these empirical findings, it is here proposed that a greater risk of HT, NIDDM, and ESRD, particularly ESRD-HT and ESRD-NIDDM, in black Americans during adulthood may be partly related to their higher risk of LBW. However, LBW is proposed here as a component factor rather than a sufficient cause or a necessary factor for the development of these diseases. The ultimate contribution of LBW to the black/white disparities regarding HT, NIDDM, and ESRD may depend not only on the black/white differences in LBW but also on the race-specific prevalences of other component factors, both environmental/behavioral and genetic, that may or may not require the presence of LBW to cause each of these diseases.

Research paper thumbnail of Impact of years of dialysis therapy on mortality risk and the characteristics of longer term dialysis survivors

American Journal of Kidney Diseases, 2002

With improving survival and a decreasing probability of receiving a transplant, patients with end... more With improving survival and a decreasing probability of receiving a transplant, patients with end-stage renal disease (ESRD) are more likely to remain on hemodialysis therapy for more years than in the past. This study evaluates the effect of years on dialysis (vintage) on relative risk (RR) for death with and without adjustment for comorbidities and treatment factors. It also compares characteristics of patients on hemodialysis therapy for 7 years or longer with those on hemodialysis therapy for 1 to 7 years. Data were combined from two special US Renal Data System studies, the Case Mix Adequacy Study and Waves 1, 3, and 4 of the Dialysis Mortality and Morbidity Study. Excluding the first year of dialysis, 12,687 patients were studied during a 2-year follow-up, censoring at transplantation or loss to follow-up. Unadjusted analysis (vintage 1 to < 2 years as referent) showed that the risk for death remained nearly the same until the end of year 7 of dialysis therapy, after which the risk decreased significantly. However, with adjustment for demographics, comorbidities, and treatment factors, vintage was significantly associated with increased mortality risk during years 2 to less than 8 (RR = 1.12 to 1.30; P < 0.05). Vintage was independently associated with increased adjusted mortality among patients with and without diabetes until approximately 6 to less than 8 years of dialysis therapy. Patients on dialysis therapy for 7 years or longer were significantly (P < 0.05) more likely to be women, younger, and have lower phosphorus levels, higher hematocrits, and higher delivered dialysis doses. We conclude that adjusted mortality risk does not decrease with years on dialysis therapy, and modifiable factors deserve greater attention to improve survival among patients with ESRD with and without diabetes treated by hemodialysis.

Research paper thumbnail of Health-related quality of life among dialysis patients on three continents: The Dialysis Outcomes and Practice Patterns Study

Kidney International, 2003

s We used the 36-item Short-Form Health Survey to compare health-related quality of life (HRQOL) ... more s We used the 36-item Short-Form Health Survey to compare health-related quality of life (HRQOL) between 104 dialysis patients in Seattle, WA, and 2,178 patients in Aichi, Japan. Compared with Aichi patients, Seattle patients had lower scores on three scales related to physical HRQOL: Physical Functioning (PF; P = 0.03), Role-Physical (RP; P = 0.004), and Vitality (VT; P < 0.001). However, scores related to mental HRQOL were higher for Seattle patients compared with those of Aichi patients, which included scores for Role-Emotional (RE; P --0.005) and Mental Health (MH; P < 0.001). Scores for Bodily Pain, General Health Perception, and Social Functioning did not differ significantly between the two groups. These differences persisted even after potential confounding factors were controlled for. However, after taking into account national norm data for the United States and Japan, differences in PF and VT disappeared, whereas differences in RP, RE, and MH persisted. These results suggest that the higher scores for PF and VT in Aichi patients were partly explained by the higher physical HRQOL of the Japanese general population. Although these data may not be representative of the total dialysis populations in the United States and Japan, they suggest potential differences in HRQOL between patients in the two countries. Additional research is needed to confirm these results and understand the factors associated with these differences. The findings suggest the need for further attention to the physical limitations of US dialysis patients and the mental health of Japanese dialysis patients.

Research paper thumbnail of Depression as a predictor of mortality and hospitalization among hemodialysis patients in the United States and Europe

Kidney International, 2002

In recent decades, important advances have been made hemodialysis patients in the United States a... more In recent decades, important advances have been made hemodialysis patients in the United States and Europe.

Research paper thumbnail of Health-related quality of life as a predictor of mortality and hospitalization: The Dialysis Outcomes and Practice Patterns Study (DOPPS

Kidney International, 2003

Research paper thumbnail of Screening for depression in hemodialysis patients: Associations with diagnosis, treatment, and outcomes in the DOPPS

Kidney International, 2004

Background. Depressive symptoms and depression are the most frequent psychologic problems reporte... more Background. Depressive symptoms and depression are the most frequent psychologic problems reported by hemodialysis patients. We assessed the prevalence of depressive symptoms and physician-diagnosed depression, their variations by country, and associations with treatment by antidepressants among hemodialysis patients. We also assessed whether depressive symptoms were independently associated with mortality, hospitalization, and dialysis withdrawal.

Research paper thumbnail of Health-related quality of life in the Dialysis Outcomes and Practice Patterns Study (DOPPS

American Journal of Kidney Diseases, 2004

Background: Health-related quality of life (HRQOL), a validated system of measuring patients' phy... more Background: Health-related quality of life (HRQOL), a validated system of measuring patients' physical, mental, and social well-being, can be of particular use in populations with chronic conditions, such as end-stage renal disease (ESRD). Methods: The Dialysis Outcomes and Practice Patterns Study (DOPPS) has used the Kidney Disease Quality of Life Short Form (KDQOL-SF) to measure ESRD patients' self-assessment of functioning and well-being, as measured by 3 component scores: physical component summary (PCS, 4 subscales), mental component summary (4 subscales), and kidney disease component summary (11 subscales). Several DOPPS studies examined HRQOL's associations with mortality and hospitalization by country, ethnicity (United States only)

Research paper thumbnail of Health-related quality of life and associated outcomes among hemodialysis patients of different ethnicities in the United States: The Dialysis Outcomes and Practice Patterns Study (DOPPS

American Journal of Kidney Diseases, 2003

Background: In the United States, an association between mortality risk and ethnicity has been ob... more Background: In the United States, an association between mortality risk and ethnicity has been observed among hemodialysis patients. This study was developed to assess whether health-related quality of life (HRQOL) scores also vary among patients of different ethnic backgrounds. Associations between HRQOL and adverse dialysis outcomes (ie, death and hospitalization) also were assessed for all patients and by ethnicity. Methods: Data are from the Dialysis Outcomes and Practice Patterns Study for 6,151 hemodialysis patients treated in 148 US dialysis facilities who filled out the Kidney Disease Quality of Life Short Form. We determined scores for three components of HRQOL: Physical Component Summary (PCS), Mental Component Summary (MCS), and Kidney Disease Component Summary (KDCS). Patients were classified by ethnicity as Hispanic and five non-Hispanic categories: white, African American, Asian, Native American, and other. Multiple linear regression models were used to estimate differences in HRQOL scores among ethnic groups, using whites as the referent category. Cox regression models were used for associations between HRQOL and outcomes. Regression models were adjusted for sociodemographic variables, delivered dialysis dose (equilibrated Kt/V), body mass index, years on dialysis therapy, and several laboratory/comorbidity variables. Results: Compared with whites, African Americans showed higher HRQOL scores for all three components (MCS, PCS, and KDCS). Asians had higher adjusted PCS scores than whites, but did not differ for MCS or KDCS scores. Compared with whites, Hispanic patients had significantly higher PCS scores and lower MCS and KDCS scores. Native Americans showed significantly lower adjusted MCS scores than whites. The three major components of HRQOL were significantly associated with death and hospitalization for the entire pooled population, independent of ethnicity. Conclusion: The data indicate important differences in HRQOL among patients of different ethnic groups in the United States. Furthermore, HRQOL scores predict death and hospitalization among these patients. Am J Kidney Dis 41:605-615.

Research paper thumbnail of The low birth weight hypothesis as a plausible explanation for the black/white differences in hypertension, non-insulin-dependent diabetes, and end-stage renal disease

American Journal of Kidney Diseases, 1995

It is well known that black Americans have a higher risk for low birth weight (LBW) than white Am... more It is well known that black Americans have a higher risk for low birth weight (LBW) than white Americans. In addition, blacks are at a higher risk for hypertension (HT), non-insulin dependent diabetes mellitus (NIDDM), and end-stage renal disease (ESRD), particularly ESRD attributed to HT (ESRD-HT) and NIDDM (ESRD-NIDDM). It has been shown that LBW is associated with postpartum anatomic and functional alterations in the kidney and pancreas as well as with progressive renal damage in animals and increased risk for HT and NIDDM during adulthood in humans. Based on these empirical findings, it is here proposed that a greater risk of HT, NIDDM, and ESRD, particularly ESRD-HT and ESRD-NIDDM, in black Americans during adulthood may be partly related to their higher risk of LBW. However, LBW is proposed here as a component factor rather than a sufficient cause or a necessary factor for the development of these diseases. The ultimate contribution of LBW to the black/white disparities regarding HT, NIDDM, and ESRD may depend not only on the black/white differences in LBW but also on the race-specific prevalences of other component factors, both environmental/behavioral and genetic, that may or may not require the presence of LBW to cause each of these diseases.

Research paper thumbnail of Impact of years of dialysis therapy on mortality risk and the characteristics of longer term dialysis survivors

American Journal of Kidney Diseases, 2002

With improving survival and a decreasing probability of receiving a transplant, patients with end... more With improving survival and a decreasing probability of receiving a transplant, patients with end-stage renal disease (ESRD) are more likely to remain on hemodialysis therapy for more years than in the past. This study evaluates the effect of years on dialysis (vintage) on relative risk (RR) for death with and without adjustment for comorbidities and treatment factors. It also compares characteristics of patients on hemodialysis therapy for 7 years or longer with those on hemodialysis therapy for 1 to 7 years. Data were combined from two special US Renal Data System studies, the Case Mix Adequacy Study and Waves 1, 3, and 4 of the Dialysis Mortality and Morbidity Study. Excluding the first year of dialysis, 12,687 patients were studied during a 2-year follow-up, censoring at transplantation or loss to follow-up. Unadjusted analysis (vintage 1 to &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 2 years as referent) showed that the risk for death remained nearly the same until the end of year 7 of dialysis therapy, after which the risk decreased significantly. However, with adjustment for demographics, comorbidities, and treatment factors, vintage was significantly associated with increased mortality risk during years 2 to less than 8 (RR = 1.12 to 1.30; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Vintage was independently associated with increased adjusted mortality among patients with and without diabetes until approximately 6 to less than 8 years of dialysis therapy. Patients on dialysis therapy for 7 years or longer were significantly (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) more likely to be women, younger, and have lower phosphorus levels, higher hematocrits, and higher delivered dialysis doses. We conclude that adjusted mortality risk does not decrease with years on dialysis therapy, and modifiable factors deserve greater attention to improve survival among patients with ESRD with and without diabetes treated by hemodialysis.

Research paper thumbnail of Health-related quality of life among dialysis patients on three continents: The Dialysis Outcomes and Practice Patterns Study

Kidney International, 2003

s We used the 36-item Short-Form Health Survey to compare health-related quality of life (HRQOL) ... more s We used the 36-item Short-Form Health Survey to compare health-related quality of life (HRQOL) between 104 dialysis patients in Seattle, WA, and 2,178 patients in Aichi, Japan. Compared with Aichi patients, Seattle patients had lower scores on three scales related to physical HRQOL: Physical Functioning (PF; P = 0.03), Role-Physical (RP; P = 0.004), and Vitality (VT; P < 0.001). However, scores related to mental HRQOL were higher for Seattle patients compared with those of Aichi patients, which included scores for Role-Emotional (RE; P --0.005) and Mental Health (MH; P < 0.001). Scores for Bodily Pain, General Health Perception, and Social Functioning did not differ significantly between the two groups. These differences persisted even after potential confounding factors were controlled for. However, after taking into account national norm data for the United States and Japan, differences in PF and VT disappeared, whereas differences in RP, RE, and MH persisted. These results suggest that the higher scores for PF and VT in Aichi patients were partly explained by the higher physical HRQOL of the Japanese general population. Although these data may not be representative of the total dialysis populations in the United States and Japan, they suggest potential differences in HRQOL between patients in the two countries. Additional research is needed to confirm these results and understand the factors associated with these differences. The findings suggest the need for further attention to the physical limitations of US dialysis patients and the mental health of Japanese dialysis patients.