Table 2

Details of the studies included in the review
Study
 N Dialysis type
 Mean age (years)
 Mean time on dialysis (months)
 Gender % male
 Main statistical analysis
 Predictors of adherence
 Adherence assessment
 Non-adherence definition
 % Non-adherent






Demographic
 Clinical
 Psychosocial


Bame et al, 1993 U.S. [12]
 1230 HD
 57
 Not stated
 47%
 Multiple logistic regression
 Age*, income*, gender, ethnicity, marital status, education
 Not assessed
 Not assessed
 Serum phosphorus
 >6 mg/dl
 50%
Betts & Crotty, 1988 U.S.[42]
 46 HD
 Not stated
 Not stated
 33%
 Correlations
 Age, education
 Time on dialysis
 Response to illness
 Serum phosphorus
 > 5 mg/dl
 74%
Blanchard et al, 1990 U.S.[38]
 40 HD 40 PD
 50
 Not stated
 48%
 Correlations
 Gender
 Time on dialysis
 Not assessed
 Self report
 Reporting ever missing a dose
 28%
Boyer et al, 1990 U.S.[13]
 60 HD
 Not stated
 Not stated
 71%
 Correlations, multiple regression
 Age*, marital status*, gender, ethnicity, income, education
 Time on dialysis
 Social support*
 Serum phosphorus
 Not dichotomised
 Not stated
Christensen et al, 1994 U.S.[14]
 52 HD 34 PD
 49
 73
 53%
 Hierarchical regression
 Age**, gender, marital status, education
 Diabetic status, time on dialysis, transplant history, type of dialysis
 Information vigilance, active coping
 Serum phosphorus
 Not dichotomised
 Not stated
Christensen et al, 1995 U.S.[15]
 72 HD or PD
 46
 73
 54%
 Correlations, stepwise regression
 Age*, education
 Time on dialysis, transplant history
 Neuroticism, extraversion, openness to experience, agreeableness, conscientiousness*
 Serum phosphorus
 Not dichotomised
 Not stated
Christensen et al, 1996a U.S.[44]
 52 HD
 59
 62
 59%
 Regression
 Age, education, gender
 Diabetic status, time on dialysis
 Neuroticism, private body consciousness, illness related physical impairment
 Serum phosphorus
 Not dichotomised
 Not stated
Christensen et al, 1996b U.S. [16]
 67 HD 14 PD
 55
 70
 49%
 Regression
 Age **, education, gender
 Diabetic status*, type of dialysis, time on dialysis
 Perceived health competence*, health locus of control
 Serum phosphorus
 Not dichotomised
 Not stated
Christensen et al, 1997a U.S.[33]
 51 HD
 57
 51
 59%
 Correlation, hierarchical regression
 Age, education, gender
 Diabetic status, time on dialysis
 Monitoring attentional style, trait anxiety, internal health locus of control, control appraisal, avoidant coping
 Serum phosphorus
 Not dichotomised
 Not stated
Christensen et al, 1997b U.S.[43]
 48 HD
 56
 65
 54%
 Correlations, hierarchical regression
 Age, education, gender
 Diabetic status, time on dialysis
 Cynical hostility*, health locus of control
 Serum phosphorus
 Not dichotomised
 Not stated
Cummings et al, 1982 U.S.[22]
 116 HD
 55
 29
 54%
 Correlations, regression
 Age*, gender, income, education
 Time on dialysis, transplant history, regimen complexity*
 Susceptibility, severity, benefits*+, barriers+, knowledge of purpose of regimen*, social support (family and friends), support from medical staff+, family problems+
 Serum phosphorus Self report
 >5.5 mg/dl
 70% (based on serum phosphorus)
Curtin et al, 1999 U.S.[49]
 135 HD
 63
 Not stated
 47%
 Chi-square
 Ethnicity###, age, gender, employment status, education
 Cause of renal failure, no. comorbidities, time on dialysis
 Not assessed
 Electronic monitoring (used in analysis)
Pill count
Self report
 Overdosing/underdosing/missing more than 20% prescribed doses
 73% (based on electronic monitoring)
Eitel et al, 1998 U.S.[27]
 40 HD 45 PD
 55
 40
 61%
 Correlations
 Not assessed
 Not assessed
 Efficacy expectations**, effort attributions, self control
 Serum phosphorus (used in analysis)
Self report
Staff ratings
 Not dichotomised
 Not stated
Gago et al, 2000 Spain[35]
 121 HD
 63
 37
 56%
 T-tests
 Gender, age, living arrangements
 Cause of ESRD, time on dialysis
 Knowledge
 Not clear
 Not clear
 46%
Hilbert, 1985 U.S.[29]
 26 HD
 47
 54
 35%
 Correlations, ANOVA
 Age, income, education, social class, religion, gender, significant other
 No. times hospitalised, time on dialysis+
 Directive guidance social support+, affection social support
 Composite self report scale – adherence to medication, fluid and diet (used in analysis) Serum phosphorus
 Not dichotomised
 Not stated
Horne et al, 2001 U.K.[17]
 47 HD
 49
 53
 49%
 Correlations
 Age+, gender, education
 Duration of ESRD, time on dialysis, no. prescribed medicines
 Beliefs about medication (concerns ++, perceived need, harm, overuse)
 Self report
 Those who reported sometimes, often or very often deliberately missing a dose of their medication.
 26%
Leggat et al, 1998 U.S.[18]
 6251 HD
 58
 54
 50%
 Logistic regression
 Age***, ethnicity*, smoker*, gender, education, living arrangements
 Time on dialysis, diabetic status, transplant history
 Not assessed
 Serum phosphorus
 >7.5 mg/dl
 22%
Lin & Liang, 1997 China[39]
 86 HD
 55
 42
 45%
 Correlations
 Not assessed
 Not assessed
 Health locus of control+++, **
 3 composite measures: Lab reports (including serum phosphorus)
Self report – fluid, diet and medication adherence
Nurses' assessment – fluid, diet and medication adherence
 >4.59 mg/dl
 61% (based on serum phosphorus)
Moran et al, 1997 U.S.[45]
 56 HD
 57
 46
 64%
 Regression
 Age, gender, education
 Time on dialysis, diabetic status, transplant history**
 Social support, conscientiousness
 Serum phosphorus
 Not dichotomised
 Not stated
Morduchowicz et al, 1993 Israel[46]
 50 HD
 56
 66
 60%
 Multivariate and stepwise regression
 Education ***, ethnicity*, gender, age, place of birth, religious observance, marital status, no. children, whether accompanied to session, economic status, living arrangements
 Previous PD dialysis, time on dialysis
 Not assessed
 Serum phosphorus
 Not dichotomised
 Not stated
O'Brien, 1980 U.S.[28]
 63 HD
 Not stated
 Not stated
 54%
 ANOVA, correlations, regression
 Age, gender, marital status++, ethnicity, education, occupation, type of household
 Time on dialysis
 Significant others' expectations regarding adherence+++
 Composite self report scale – dialysis attendance, diet, fluid and medication
 Not stated
 Not stated
Reiss et al, 1986 U.S.[47]
 23 HD
 48
 8
 57%
 Correlations
 Family income, marital status, years married, family size, education
 Not assessed
 Problem solving (coordination and closure), family intelligence
 Serum phosphorus
 Not dichotomised
 Not stated
Schlebusch & Levin, 1982 South Africa[34]
 25 HD or PD
 38
 Not stated
 48%
 Mann-Whitney test
 Not assessed
 Organicity (cortical dysfunction)$
 Intelligence, personality$$
 Composite staff rating – including adherence to medication and diet
 Not stated
 44%
Schneider, 1992 U.S.[19]
 137 HD
 51
 26
 54%
 Multiple regression
 Age***, gender, ethnicity, education
 Time on dialysis, frequency of physician contact
 Health locus of control***
 Serum phosphorus
 Not dichotomized
 Not stated
Sherwood, 1983 U.S.[30]
 55 HD
 46
 48
 66%
 Correlations
 Not assessed
 Not assessed
 Family understanding, family organisation*, supportive family**,+++
 Serum phosphorus Composite self-report measure – diet, fluid and medication
 Not stated
 Not stated
Stamatakis et al, 1997 U.S.[20]
 17 HD
4 PD
 53
 Not stated
 48%
 Anova, chi-square, multiple regression
 Age*, gender, ethnicity education, occupation, marital status
 Type of dialysis, cause of ESRD, transplant history
 Knowledge*
 Serum phosphorus Self report
 Not stated
 Not stated
Steidl et al, 1980 U.S.[31]
 22 HD
1 PD
 43
 22
 57%
 Correlations
 Not assessed
 Medical assessment
 Family functioning$$$
 Composite staff assessment – dialysis attendance/medication and diet adherence
 Not stated
 Not stated
Takaki et al, 2003 Japan[21]
 484 HD
 60
 98
 66%
 Correlations, multiple regression
 Age***, gender
 Time on dialysis***
 Not assessed
 Serum phosphorus
 Not dichotomised
 Not stated
Tomasello et al. 2004 U.S.[3]
 129 HD 59 PD
 60
 46
 Not stated
 ANOVA
 Age
 Time on dialysis, diabetic status, tablet burden*
 Not assessed
 Self report
Serum phosphorus
 Reporting taking less than 80% medication as prescribed
>5.5 mg/dl
 38% (based on self report) 51% (based on serum phosphorus)
Tracy et al, 1987 U.S.[40]
 15 HD
 52
 0 (starting dialysis)
 67%
 Correlations, ANOVA
 Not assessed
 Not assessed
 Personality*, depression*, family environment
 Composite measure – serum phosphorus and interdialytic weight
 Not stated
 Not stated
Vives et al, 1999 Spain[41]
 31 HD
 63
 35
 74%
 Mann Whitney, Wilcoxon, T-test
 Age, gender
 Duration of treatment
 Health locus of control
 Composite score based on serum phosphorus, serum potassium and interdialytic weight
 >6.01 mg/dl
 Not stated
Weed-Collins & Hogan, 1989 U.S.[26]
 30 HD
 Not stated
 Not stated
 43%
 Correlations
 Not assessed
 Not assessed
 Knowledge of phosphate binders, susceptibility, severity, benefits, barriers*
 Serum phosphorus
 >5.5 mg/dl
 64%
Wenerowicz et al, 1978 U.S.[37]
 19 HD
 36
 7
 68%
 Chi-square, t-test
 Not assessed
 Not assessed
 Health locus of control *
 Serum phosphorus
 >4.5 mg/dl
 68%
Wiebe & Christensen, 1997 U.S.[48]
 70 HD
 56
 141
 60%
 Stepwise, hierarchical regression
 Age, gender, education, marital status
 Diabetic status, time on dialysis
 Conscientiousness, susceptibility, severity, benefits, barriers
 Serum phosphorus
 Not dichotomised
 Not stated

Note: HD = hemodialysis, PD = peritoneal dialysis, ESRD = End stage renal disease

* p < 0.05 **p < 0.01 ***p < 0.001 relationship with serum phosphorus levels, + p < 0.05 ++p < 0.01 +++p < 0.001 relationship with self report adherence, # p < 0.05 ##p < 0.01 ###p < 0.001 relationship with electronic monitoring, $p < 0.05 $$ < 0.01 $$$p < 0.001 relationship with staff ratings of adherence

Karamanidou et al. BMC Nephrology 2008 9:2   doi:10.1186/1471-2369-9-2