PENAPISAN TEKNOLOGI DIAGNOSTIKBambang Udji Djoko Rianto

The technology assesment iterative loop

TUJUANMemahami berbagai masalah terkait dg penggunaan teknologi diagnostik bidang kedokteran/kesehatanMelakukan penilaian kritis thd penggunaan suatu teknologi diagnostik

PENDAHULUANKetepatan diagnosis: kunci sukses penanganan pasienPengembangan teknologi diagnostik membawa manfaat dan dampak

Disease/non diseaseTEKNOLOGI DIAGNOSTIKAccurateSafeTherapeutic impactPendahuluan

Jumlah & rerata CT-scanner/1 juta penduduk

Negara

Jumlah CT Scanner

CT scanner/juta penduduk

1986

1988

1986

1988

AS

Jepang

Perancis

Belgia

Jerman Barat

Denmark

Belanda

Inggris

Itali

3000

3300

264

64

423

23

45

149

210

4991

5448

350

118

595

?

83

204

338

12.8

27.5

4.7

6.4

6.9

4.6

3.2

2.7

3.5

21.7

44.3

6.3

12.1

9.8

?

5.7

3.6

5.9

Jumlah & rerata MRI/ 1 juta penduduk

Negara

Jumlah MRI

Rerata MRI/juta penduduk

1986

1988

1986

1988

AS

Jepang

Perancis

Belgia

Jerman Barat

Belanda

Inggris

Itali

110

10

29

7

41

2

14

13

1150

256

34

7

91

7

28

29

0.5

0.1

0.5

0.7

0.7

0.4

0.3

0.2

5.0

2.0

0.6

0.7

1.5

0.5

0.5

0.5

Test-treatment thresholds

Penilaian teknologi diagnostikTingkat akurasiTingkat ketelitianPeruntukan teknologi diagnostikEvaluasi teknis Peranan dalam proses pengambilan keputusan terapetikPeranan dalam penurunan morbiditas dan mortalitasKeuntungan bagi klinisiKeuntungan bagi pasien

Diagnostic accuracySensitivitasSpesifisitasLikelihood ratio

DEFINISISensitivity: proporsi hasil test positif pada kelompok penderitaSpecificity: proporsi hasil test negatif pada kelompok orang tanpa penyakit Positive PV: probabilitas penyakit pada penderita dengan hasil test positifNegative PV: probabilitas seseorang dengan hasil test negatif untuk benar-benar bebas dari penyakit

Sensitivity=a / (a+c)Specificity=d / (b+d)Accuracy=(a+d) / N+ PV=a / (a+b)- PV=d/ (c+d)Prevalence=(a+c) / N+-+Gold StandardHasiltestabcd-a+bc+da+cb+dN

2 Pendekatan ttg penampilan diagnosisPrevalensiSensitivitas/SpesifisitasNilai ramalPre-testprobabilityRasiokemungkinanPost-testprobability

Likelihood RatioLikelihood ratio positif: rasio hasil tes positip yang dijumpai pada kelompok sakit dan kelompok tidak sakit Likelihood ratio negatif: rasio hasil tes negatip yang dijumpai pada kelompok sakit dan kelompok tidak sakit

+-+Gold StandardHasiltestabcd-a+bc+da+cb+dN

Lieklihood ratio>10 atau < 0,1, menghasilkan perubahan yg besar dari pre dan post test probability. Dan sering conclusive5-10 dan 0,1-0,2, perubahan sedang2-5 daan 0,2-0,5 perubahan kecil (kadang-kadang penting)1-2 dan 0,5-1, mengubah probability kecil sekali (dan jarang penting)

Ketelitian diagnosisSkala nominal: un-weighted kappaSkala ordinal: weighted kappaSkala interval/rasio: intra-class coefficient correlation (ICC), CV

Peruntukan teknologi diagnostikMenegakkan diagnosisMenyingkirkan diagnosisSkrining

Technical evaluationProsedur sederhanaRisiko minimalInterpretasi jelas (risiko false positive rendah)Risiko kesalahan pembacaan akibat kesalahan prosedur operasional kecilKetergantungan terhadap rekonfirmasi diagnosis atau second opinion kecil

Diagnostic impactMendeteksi penyakit pada fase diniRekonfirmasi terhadap prosedur diagnostik sebelumnyaHasil mempengaruhi prognosisMengurangi risiko keraguan

Therapeutic impactMensupport therapeutic decision making processEarly treatmentMengubah kebijakan terapi yang sudah diputuskan

Health impactEarly warning systemMorbiditas & mortalitas turunQuality of health careReassurance

Seberapa besar kontribusinya terhadap therapeutic decision making processPrompt actionKeuntungan yang diperoleh melebihi cost yang dikeluarkanMembantu menetapkan terapi yang lebih do more good than harm

Prompt treatmentEarly diagnosismorbiditasmortalitasSeberapa besar kontribusinya terhadap penurunan mortalitas dan morbiditas

Apa keuntungannya bagi klinisiMenghilangkan keraguan diagnosisImproving confidenceLebih terfokus pada pilihan terapiMengurangi risiko malpracticeImproving quality of care

Morbidity/mortalityQuality of lifeDisabilityOpportunity costPatient satisfactionApa keuntungannya bagi pasien

Should general practitioner perform diagnostic tests on patients before prescribing antibiotics?,BMJ 318, 799-802Kendali resistensi thd antibiotik tergantung perilaku peresepan yg rassional oleh dokter umum.Pemeriksaan mikrobiologis merupakan dasar pemberian antibiotik yg rasional. Tetapi hal ini memiliki kendalaSalah satu cara untuk mengatasi masalah ini di Denmark melakukan pemeriksaan mikrobiologis menggunakan mikroskop fase kontras dan kit diagnostik sederhana (near patient testing)

Keuntungan near patient testingHasil pemeriksaan lebih cepat tersedia dan keputusan dapat segeraa diambilBirokrasi dikurangi. Menghemat waktu, mengurangi problem komunikasi, menghemat uang, lebih murah dan mendapat tambahan pendapatan.

Isu tentang mutuBaku pemeriksaan ditempat praktek harus seimbang dg yg di laboratoriumSyarat pemeriksaan: sederhana, cepat, handal, mudah dibaca dan diinterpretasikanContoh: pemeriksaan mikroskopis fase kontras untuk ISK, vaginitis/vaginosis, pharyngotonsilitis, dermatophytosis, perianal pruritus, mononukleosis

Kepentingan near patient testsPaling penting dilakukan untuk discharge vagina, dysuria, pharyngitis.Pemeriksaan mikroskopis fase kontras di tempat praktek umum lebih teliti dibanding di laboratoriumBerfungsi sbg skrining pemeriksaan berikutnya, misalnya biakan, pemeriksaan Chlamydia, athropic vaginitis

Aspek uji diagnosis dalam praktek dokter umumApakah uji/pemeriksaan layak dan valid? Perlu selektif, pelatihan dan kendali mutu. Grup A streptococcus vs ASTO. Test strip vs metode skoring klinis.Apakah uji/pemeriksaan mempercepat kesembuhan? Penurunan keluhan vs kekambuhan; 50% bakteriuria akan sembuh dlm waktu 3 hari tanpa antibiotik

Aspek-aspek uji diagnosis dalam praktek dokter umumApakah uji/pemeriksaan mencegah komplikasi?Apakah pasien diuntungkan?Apakah uji/pemeriksaan cost-effective?

KesimpulanPemeriksaan diagnosis untuk infeksi akut dilakukan jika ada bukti yg kuat ttg validitas, kelayakan, dan cost-effectivenesSebelum ada bukti yg kuat dokter umum dianjurkaan untuk memberikan obat simtomatis untuk infeksi yg paling sering dijumpai tanpa tergantung pd pemeriksaan diagnosis maupun antibiotik

The impact of medical imaging on physicians diagnostic and therapeutic thinking Eur. Radiol. 8: 488-90

PendahuluanAda perubahan kecenderungan bahwa pemeriksaan radiologi requested dari pada orderedPermintaan pemeriksaan sering didiskusikan dalam pertemuan antara dokter klinis dan radiolog dengan memperhatikan kondisi klinis pasien, penampilan diagnosis dari bbrp pilihan, biaya, ketersediaan, daan expertise.

5 tahap dalam penilaian teknologi radiologiTechnical performanceDiagnostic performanceDiagnostic impact keputusan diagnostikDiagnostic impact keputusan terapiImpact on health

Diagnostic thinkingDulu diagnosis pd pasien rawat jalan dpt ditegakkan dg anamnesis yg baik dan pemeriksaan fisikModern radiologi mungkin dpt mengubah fenomena iniRadiolog dpt bekerja sama dg klinisi dlm penatalaksanaan pasien

Diagnostic thinkingDiagnosis klinis: peran radiologi kurang tampak apabila klinisi memberikan diagnosis klinis terlalu luas, begitu juga sebaliknyaDiagnostic confidence, ditetapkaan dg bbrp cara: pre-test probability, hasil V/Q scan, 10 point scale, VAS, LR, diagnostic entropy

Diagnostic thinkingDisplacement of other investigations: pemeriksaan alat lama dan alat baru, alat baru dpt menggantikan alat lama, misalnya MRI pada meatus auditorius interna menggantikan pemeriksaan neurofisiologisHealth economists and statisticians

Therapeutic thinkingPilihan terapi tersedia setelah diagnosis ditegakkan. Pilihan ini juga tergantung dari kwalifikasi pengirimPengembangan algoritme

How Often Should We Screen for Cervical Cancer? AU: Sarah Feldman, M.D., M.P.H. SO: New Eng J of Med, Volume 349, Number 16; October 16, 2003 Over the past 60 years, the mortality from cervical cancer has decreased dramatically. Much of the reduction has been due to the widespread use of the Papanicolaou test, which has enabled clinicians to detect cervical intraepithelial neoplasia before it progresses to cervical cancer and to detect cervical cancer at an early stage. When cervical cancer is detected early, the five-year survival rate is more than 90 %

PAP Smear test> 80 % of women undergoing screening in any two-year period and > 90 % having been screened at least once. Questions remain about optimal screening strategies. One key question is the optimal frequency of testing. Costbenefit analyses have suggested that lifelong annual screening may not result in substantially better outcomes than less frequent screening and is much more costly. With this in mind, the American Cancer Society recently revised its guidelines for screening

PAP Smear testRecommending intervals between screenings ranging from one to three years, depending on several factors, such as age, screening history, type of Papanicolaou smear, and history of immunosuppression. Other guidelines have also suggested screening less frequently than annually after three consecutive normal annual Papanicolaou tests and pelvic examinations. Yet there are not many data to support these recommendations.

Risk of Cervical Cancer Associated with Extending the Interval between Cervical-Cancer ScreeningsAU: Sawaya et alSO: New Eng J of Medicine, Volume 349, Number 16; October 16, 2003

MethodsWe determined the prevalence of biopsy-proven cervical neoplasia among 938,576 women younger than 65 years of age, stratified according to the number of previous consecutive negative Papanicolaou tests. Using a Markov model that estimates the rate at which dysplasia will progress to cancer, we estimated the risk of cancer within three years after one or more negative Papanicolaou tests, as well as the number of additional Papanicolaou tests and colposcopic examinations that would be required to avert one case of cancer given a particular interval between screenings.

ResultAmong 31,728 women 30 to 64 years of age who had had three or more consecutive negative tests The prevalence of biopsy-proven cervical intraepithelial neoplasia of grade 2 was 0.028 % The prevalence of grade 3 neoplasia was 0.019 %None of the women had invasive cervical cancer

ResultAccording to our model, the estimated risk of cancer with annual Papanicolaou tests for three years :2 in 100,000 among women 30 to 44 years of age, 1 in 100,000 among women 45 to 59 years of age, 1 in 100,000 among women 60 to 64 years of age; these risks would be 5 in 100,000, 2 in 100,000, and 1 in 100,000, respectively, if screening were performed once three years after the last negative test.

ResultTo avert one additional case of cancer by screening 100,000 women annually for three years rather than once three years after the last negative test, an average of 69,665 additional Papanicolaou tests and 3861 colposcopic examinations would be needed in women 30 to 44 years of age and an average of 209,324 additional Papanicolaou tests and 11,502 colposcopic examinations in women 45 to 59 years of age.

ConclusionAs compared with annual screening for three years, screening performed once three years after the last negative test in women 30 to 64 years of age who have had three or more consecutive negative Papanicolaou tests is associated with an average excess risk of cervical cancer of approximately 3 in 100,000.

Colorectal cancer screening: an overview of available and current recommendationsEarly DS, Southern Medical Journal, 92 (3):258-265

Colorectal cancer screeningSkrining pd asimtomatik dpt menurunkan insidensi dan kematianDatabase medline: artikel yg memuat rasional skrining kanker colorectal, metode yg digunakan, hasil guna dan rekomendasi yg digunakan saat iniHasil: metode: flexible sigmoidoscopy, fecal blood test, barium enema, colonoscopy. Metode yg digunakan dan frekwensi skrining tergantung dr risiko

Colorectal cancer screeningPenerimaan skrining oleh pasien dan dokter belum optimalMasih diperdebatkan: Potensi skrining untuk mencegah kematian dari ca colorectal, Cost effectiveness jika digunakan untuk populasi umum.

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