pku watch
Evaluation of quality of life and description
by Eva Simon, Martin Schwarz, Judith Roos, Nico
Dragano, Max Geraedts, Johannes Siegrist,
of the socio-demographic state in
Gudrun Kamp and Udo Wendel from Heinrich
adolescent and young adult patients with
Heine University, Duesseldorf, Germany
phenylketonuria (PKU)
Background
the control collective. The mean values for capacity of per-
Phenylketonuria (PKU, McKusick 261600) is the most com-
formance and well being amount to 2.7–3.2 in the patient
mon error of the amino acid metabolism with an incidence
group and to 2.5–3.0 in the control collective. The mean
of 1:12.000 in Germany. Due to a blockage in its degrada-
number of disease-specific symptoms in the patient collec-
tion the essential amino acid phenylalanine accumulates
tive was 1 ± 0.9. Frequent symptoms were headache and
resulting in severe mental retardation and neurological
poor memory.
abnormalities. Treatment of PKU consists of a life-long pro-
Patients older than 25 years stated more PKU-specific
tein-restricted diet with supplementation of phenylalanine-
symptoms than younger patients but the difference did not
free amino acid mixtures. With the nation-wide introduction
reach statistical significance (1.2 vs. 0.8, p = 0.08). Women
of newborn screening for PKU in Germany in the 1970s and
stated lower levels of positive mood (Score 2.5 vs. 3.0, p =
the early institution of the diet, mental retardation due to
0.02) and lower levels of psychological functioning (Score 2.7
PKU has been almost eliminated. Raised phenalanine levels
vs. 3.0, p = 0.09). Women indicated higher scores in the cat-
in pregnancy exert adverse effects on the foetus (maternal
egory ‘social wellbeing’ (Score 3.2 vs. 2.9, p = 0.09). However,
PKU with microcephaly, growth retardation, developmental
differences were small and p-values are above the defined
delay and congenital heart disease), therefore compliance
threshold (p > 0.001; Bonferroni corrected)
with treatment must be especially strict.
A great percentage of patients still lived with their parents
Substantial knowledge has been gained of the intellec-
(48% of the male and 46% of the female patients) in contrast
tual [1], neurocognitive [2,3] and psychiatric state [4-7] of
to approximately one quarter of the general population.
patients with phenylketonuria (PKU, McKusick 261600). This
The analysis of marital state revealed a higher percentage
experience allows for a vast overview but further parameters
of patients being unmarried in comparison to the general
are necessary for an overall estimation of a patient’s out-
population. This applied for the complete patient group as
come. Such important aspects of interest for the outcome of
well as for the male and female group taken separately
PKU patients are quality of life and social outcome.
(>80% vs. 50–60%). The main proportion of the unmarried pa-
After the introduction of newborn screening for PKU in the
tients were not in a steady relationship, in the male patients
1960s, the number of early diagnosed and early treated adult
this ratio was as high as 95%. While nearly half of the subjects
patients continues to increase. Normal outcome is expected
in the general population had children, this was the case in
in these patients. High quality of life, a normal social status and
only approximately 9% of the female and 18% of the male
an independent adult lifestyle are major goals of treatment.
adult patients.
Methods
Concerning school education no obvious differences
104 early-treated PKU patients aged 17 years and above,
were detected between patients and the general popula-
who formerly or actually attended the metabolic units of the
tion. The distribution of the highest professional qualifications
University Hospitals in Duesseldorf or Cologne, were invited
was the same, the only remarkable feature was that more
by mail to participate in the study. A total of 67 patients
than half of the female patients had not finished a voca-
completed and returned the standardized self-assessed
tional training at the time of the inquiry in contrast to ap-
questionnaire (response rate 64%). Time of questionnaire
proximately one third in the general population.
dispatch was July 2003.
The labour force status in the patient collective resem-
Quality of life was enquired with the Profile of Quality of
bled the status in the general population. Differences were
Life in the Chronically Ill (PLC) questionnaire [9]. The PLC is an
a higher percentage of part-time employees in the male
approved questionnaire with a satisfactory criterion validity
patient group than in the male general population, while
that has been used in a number of studies on QoL in chronic
the proportion of part time employees was slightly lower in
diseases. Data on the German population between 14 and
the female patient group than in the normal population.
92 years have been collected for comparison of patient
Conclusion
groups with a normal collective. The core module of this ap-
The analysis of the social state of PKU patients revealed a
proved questionnaire is composed of 40 Likert-scaled items
tendency towards lower or delayed autonomy, and a low
(scale 0–4) with 0 representing minimum and 4 representing
rate of forming normal adult relationships in which to have
maximum satisfaction. The items measure physical, psycho-
children. Schooling and professional career corresponded
logical and social capacity of performance and well-be-
approximately to the control collective. Quality of life mea-
ing (for details see table 1). In addition to the core module,
sured with the Profile of Quality of Life in the Chronically Ill
disease-specific symptoms depending on the investigated
(PLC) revealed mean values for capacity of performance
patient collective can be added to the questionnaire.
in the patient group in the same range as in the control
Patients were asked if they suffered from memory impair-
collective. Though every chronic disorder must be regarded
ment, headache, tremor of hands, tremor of arms and legs,
as restraining, it shows that PKU does not preclude healthy
lack of dexterity, slow reaction and skin abnormalities which
emotional adjustment when the disease is diagnosed early
are rather frequent symptoms in PKU [10-13] during the last
and treated well.
seven days before filling in the questionnaire.
Results
Abbreviations
PKU: Phenylketonuria; QoL: Quality of life; PLC: Profile of Quality of Life in the Chronically Ill.
No significant differences were detected between the
Full article and references at http://www.hqlo.com/content/6/1/25
Health and Quality of Life Outcomes 2008, 6:25doi:10.1186/1477-7525-6-25
self-assessed quality of life (QoL) in the patient group and © 2008 Simon et al; licensee BioMed Central Ltd.
NHDmag.com Aug/Sep ‘08 - issue 37 25
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36