Health-Related-Quality-of-Life Questionnaires: PLD-Q

How often do you have it? How much does it bother you?

This post was prompted by the conversation on a PKD/PLD support forum about being rejected for a UK health benefit, PIP. It gained some momentum in the journey from my brain to an actual piece of writing when I read a paper (Neijenhuis et al, 2016) on a recently finalised and validated quality of life questionnaire specifically for patients with polycystic liver disease: PLD-Q. The very simple thought I had was why couldn’t PLD patients present their completed PLD-Q to the PIP assessors as evidence of their health quality of life? 

In the UK, Personal independence Payment (PIP) is a benefit paid to people with “long term health conditions that impact on their daily life”. Not surprisingly, the assessment process entails a set of questions to identify your physical, mental and social limitations attributable to your disease. The questionnaire is generic, that is, the same one is used across the board no matter the aetiology of your disability or ill health. 

One of the earliest generic health-related-quality-of-life (HRQOL) indices was the Health Assessment Questionnaire (HAQ) from the 1980s. Its development reflected a paradigm shift from defining health outcomes based on biochemical tests or imaging to including a patient’s subjective experience of their illness. In the last 30 years the HAQ has been widely accepted and translated into over 60 languages. It has even been used to predict “successful ageing” (which, I understand, means living free of disease and replete with physical, mental and social abilities, not merely reaching old age which maybe a more sensible aim for those of us with PKD)

A plethora of HRQOL indices evolved, some generic such as Short Form-36 (SF36), Nottingham Health Profile (NHP) and the Sickness Impact Profile (SIP), and many more disease-specific scales, like the Chronic Liver Disease Questionnaire (CLDQ) and the one with a long acronym: EORT-QLQ-C30 CAT which considers specifically cancer patients. An interesting aside is that the CAT stands for computerised adaptive testing which is where your responses to the previous item are used to select the next question – you may have come across this in consumer surveys, the questions that begin “You said that you hated our shower gel, why was that?” And you wish you’d agreed it was wonderful in all aspects in order to keep the questions short. 

Disease-specific questionnaires are necessary to evaluate the effects of new treatments, to help plan future management for an individual patient and in the wider arena to measure healthcare delivery. They recognise that survival is just one aspect of disease management, that wellbeing is as important. Ideally one would use a generic index, a disease-specific tool and a domain-specific tool (function, work-role, vitality, emotional, social etc) The scores of a good disease-specific tool should correlate with disease severity and the tool should be capable of measuring small shifts in disease progression

Coming back to the PLD-Q, one might ask why it is necessary given that there are already more than four HRQOL scales used for chronic liver disease. The CLDQ, from 1999, has 27 questions assessing 6 domains: abdominal symptoms, fatigue, systemic symptoms, activity, emotional and worry about future transplant availability. It uses a Likert scale, which we have all seen even if we didn’t know what they were called – where you select a response from a range from “strongly agree” to “strongly disagree” or similar. Further refinements of liver specific questionnaires led to the very long Liver Disease Quality of Life (LDQOL) with 111 items, the shortened SF-LDQOL and the Liver Disease Sympton Index (LDSI). This is all sounding a bit like Monty Python (People’s Front of Judaea etc) and now we can add the PLD-Q. 

The development of the PLD-Q was thorough and included patient-derived information at all stages. They used PLD patients over the age of 18 with more than 20 cysts documented by imaging, excluding those who were on experimental treatments or who had had rejections or transplants. Questions were selected after literature searches, interviews with patients and clinicians and they developed and validated them in 3 cycles, each one leading to improvements. The final result is a 16-question tool, each symptom being given a frequency score and a discomfort score – that is “How often have you had …” and “how much does it bother you?”. The answers are again on a Likert scale with 6 points for the frequency element and 5 for the discomfort element. So for each question the maximum score is 11. There being 16 questions, the total score is out of 176. This was translated into a 1-100 score range for ease of use.  

The final form of the questionnaire can be found in the paper’s supplementary material, reached by the link below. I found it easy to understand and straightforward to score. Indeed it is by far easier to complete than the UK PIP questionnaire, which probably needs more than one sitting to reach the end! 

The good things about this PLD-Q tool are that it has been shown to be relevant at all stages of PLD and it is transferable geographically and demographically. The authors acknowledge that they have not shown its responsiveness – ability to reliably detect change over time – but they are currently testing this in an ongoing study. 

One interesting issue was that they could not demonstrate a consistent relationship between the PLD-Q score and the liver volume. This is in direct contrast to the Korean study I wrote about last year (Mass Effect). However the score did relate to the Gigot classification that uses imaging findings to identify people who would benefit from cyst fenestration. So patients with a Gigot type III scored higher on PLD-Q than Gigot II. I am not going to discuss scores used to select patients for liver transplants but there is the possibility that PLD-Q could be used alongside the current MELD/UKELD for PLD patients because it has to be acknowledged that PLD is an unusual situation given it has debilitating symptoms with usually normal liver function, but would be “cured” by a liver transplant. 

Management of PLD is based on symptoms, given that liver function impairment is not a feature of the disease, so it is crucial to have an effective tool to evaluate those symptoms. The PLD-Q is the first one to do this. The authors recommend using it alongside a generic HRQOL tool. Importantly, they do not charge for using it for non-commercial reasons. 

Obviously the PIP assessors are not going to change from their extremely complex HRQOL form. I have yet to complete it but have seen some of the example questions, which all appear to be dichotomous yes/no answers. Is there space for explaining the “sometimes” in greater detail? Maybe you can take a completed PLD-Q to the PIP assessment alongside your medical evidence. PIP is not intended to be disease-specific, but in my view, to be able to generalise you first need to start with the disease-specific details and how they affect your activities before you can answer a question such as “Do you have problems dressing?”. Most PLD patients and many PKD patients could say yes to this – our enlarged livers and kidneys tend to lead to a prominent middle – but will the PIP assessors really understand how hard it is to put socks on when your tummy gets in the way and compressing it makes you feel sick and short of breath? Just how do you explain that putting on your socks makes you breathless? To the non-PKD/PLD person the two seem unrelated. 

I came across a review paper that stated 80% PLD patients were asymptomatic. That is wonderful if it is true, but perhaps it is a reflection that until now there has been no reliable tool or index for assessing the symptoms.  
As a post script, I have scored myself on the PLD-Q, and am not embarrassed to say, I scored 73/176 or 45 out of 100. I believe this is probably pretty good compared to many, for once I am delighted to be under the midway point!

When tummy gets in the way …


Paper on PLD-Q (2016)

Neijenhuis, M. K., Gevers, T. J.G., Hogan, M. C., Kamath, P. S., Wijnands, T. F.M., van den Ouweland, R. C.P.M., Edwards, M. E., Sloan, J. A., Kievit, W. and Drenth, J. P.H. (2016), Development and Validation of a Disease-Specific Questionnaire to Assess Patient-Reported Symptoms in Polycystic Liver Disease. Hepatology, 64: 151–160. doi:10.1002/hep.28545

The final version of PLD-Q (scroll down to supplementary file 3): 



One response to “Health-Related-Quality-of-Life Questionnaires: PLD-Q

  1. Great article. Let’s hope this will help towards educating hepatologists about the symptoms of PLD! A lot of them still seem to be in denial about the symptoms even thought they’ve been regularly reported in the literature.

    Liked by 1 person

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